Haylou RS4 Review | 126 Data compared

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  • Avg. price: ~£45
  • Screen size: 1.78 inch
  • Battery life: 10 day/s
  • Display type: AMOLED

Haylou RS4 review. Compare 126 technical specifications and user reviews to see how it ranks among smartwatches and if it is worth buying.

5.6

Overall score

What it is: An overall evaluation of the smartwatch's quality, based on technical analyses and user reviews.

When it matters: When you need a quick reference to identify the best Smartwatches on the market.

Score components:

90.0%

5.5

Technical Score

10.0%

6.5

User score

Good
5.5

Technical Score

What it is: An assessment of the smartwatch's technical performance, covering eight key areas: performance & hardware, software, camera, connectivity, display, battery, audio, and design.

When it matters: When you want to compare Smartwatches based on technical performance and available features.

Score components:

24.0%

5.4

Health

21.0%

5.8

Fitness

16.0%

7.3

Battery

14.0%

4.3

Smart features

12.0%

3.2

Connectivity

9.0%

6.2

Display & Design

4.0%

5.8

Hardware

Good
6.5

User score

What it is: A rating that combines user reviews and the total number of reviews received by the smartwatch

When it matters: When you want to know how a smartwatch handles daily tasks and how reliable it remains over time according to user feedback.

Score components:

70.0%

8.5

User reviews

30.0%

1.9

Popularity

User score:
amazon
4.6
(6)
amazon
3.6
(4)
amazon
5.0
(1)

(Reviews last updated: Apr 2026)

Good
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    Best prices

    Best rankings

    ?

    Available: ranking among products currently available (including other versions of this product).
    All: ranking among all products in the database.

    Technical Specifications of smartwatch Haylou RS4

    Technical Score

    What it is: An assessment of the smartwatch's technical performance, covering eight key areas: performance & hardware, software, camera, connectivity, display, battery, audio, and design.

    When it matters: When you want to compare Smartwatches based on technical performance and available features.

    Score components:

    24.0%

    5.4

    Health

    21.0%

    5.8

    Fitness

    16.0%

    7.3

    Battery

    14.0%

    4.3

    Smart features

    12.0%

    3.2

    Connectivity

    9.0%

    6.2

    Display & Design

    4.0%

    5.8

    Hardware

    5.5
    Haylou RS4 has a technical score of 5.47 points, which is lower than 72.1% of smartwatches.
    User score

    What it is: A rating that combines user reviews and the total number of reviews received by the smartwatch

    When it matters: When you want to know how a smartwatch handles daily tasks and how reliable it remains over time according to user feedback.

    Score components:

    70.0%

    8.5

    User reviews

    30.0%

    1.9

    Popularity

    User score:
    amazon
    4.6
    (6)
    amazon
    3.6
    (4)
    amazon
    5.0
    (1)

    (Reviews last updated: Apr 2026)

    6.5
    Haylou RS4 has a user score of 6.54 points, which is lower than 88.3% of smartwatches.
    Popularity
    What it is: An indicator based on the number of reviews received by the smartwatch.
    When it matters: When you prefer to purchase a product chosen and reviewed by many other consumers.
    1.9
    Haylou RS4 has a popularity of 1.9 points, which is lower than 53.2% of smartphones.
    Ratio quality/price

    What it is: An indicator that combines the smartwatch's overall rating with its cost.

    When it matters: When you are looking for a smartwatch with a good balance between quality and price.

    Score components:

    60.0%

    5.6

    Overall score

    40.0%

    10

    Price

    6.9
    Haylou RS4 has a quality-to-price ratio of 6.9 points, which is lower than 66.9% of smartphones.
    Brand name
    What it is: The company that designs, sells, and supports the watch.
    When it matters: When brand ecosystem, style, or support matters to you.

    Importance: MEDIUM

    Haylou
    Heart rate monitor
    What it is: A built-in sensor that measures your pulse directly from the wrist.
    When it matters: When you want health data from your wrist during the day or night.

    Importance: HIGH

    yes
    Haylou RS4 includes a heart rate monitor. 90.4% of smartwatches include a heart rate monitor.
    Blood oxygen monitoring
    What it is: A wrist-based feature that estimates blood oxygen saturation over time.
    When it matters: When you want health data from your wrist during the day or night.

    Importance: HIGH

    yes
    Haylou RS4 supports blood oxygen monitoring. 64.4% of smartwatches support blood oxygen monitoring.
    ECG
    What it is: The ability to record a single-lead electrocardiogram from the wrist.
    When it matters: When you want health data from your wrist during the day or night.

    Importance: HIGH

    no
    Haylou RS4 does not support ECG. 15.1% of smartwatches support ECG.
    Irregular heart rate warnings
    What it is: Notifications that flag heart-rate patterns which appear unusually irregular.
    When it matters: When you want health data from your wrist during the day or night.

    Importance: MEDIUM

    no
    Haylou RS4 does not support irregular heart rate warnings. 43.7% of smartwatches support irregular heart rate warnings.
    Show more
    Accelerometer
    What it is: A motion sensor that measures acceleration, steps, gestures, and general movement.
    When it matters: When you track workouts and want better training data.

    Importance: MEDIUM

    yes
    Haylou RS4 includes an accelerometer. 99.1% of smartwatches include an accelerometer.
    Barometer
    What it is: A pressure sensor used for altitude changes, elevation estimates, and weather-related context.
    When it matters: When you run, ride, hike, or navigate without relying on your phone.

    Importance: MEDIUM

    no
    Haylou RS4 does not include a barometer. 45.6% of smartwatches include a barometer.
    Gyroscope
    What it is: A motion sensor that measures rotation and helps interpret wrist movement more accurately.
    When it matters: When you track workouts and want better training data.

    Importance: MEDIUM

    no
    Haylou RS4 does not include a gyroscope. 64.6% of smartwatches include a gyroscope.
    Cadence sensor
    What it is: A sensor input used to measure step or pedal rhythm during training.
    When it matters: When you track workouts and want better training data.

    Importance: MEDIUM

    no
    Haylou RS4 does not include a cadence sensor. 20.1% of smartwatches include a cadence sensor.
    Distance tracking
    What it is: The ability to measure how far you move during walks, runs, rides, or other activities.
    When it matters: When you track workouts and want better training data.

    Importance: MEDIUM

    yes
    Haylou RS4 supports distance tracking. 95.7% of smartwatches support distance tracking.
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    Battery life
    What it is: The typical endurance the watch can deliver on a full charge under the stated usage pattern.
    When it matters: When you do not want to charge the watch too often.

    Importance: HIGH

    Good value: >=7 days

    10 day/s
    Haylou RS4 offers a battery life of 10 day/s which is longer than that of 63.3% of smartwatches and equal to that of 6.7% of smartwatches.
    Battery life in training mode
    What it is: The expected endurance while workout tracking and related training functions are active.
    When it matters: When you do not want to charge the watch too often.

    Importance: HIGH

    Good value: >=36.8 h

    ?
    Battery life with GPS on
    What it is: The expected runtime when satellite tracking stays active throughout use.
    When it matters: When you do not want to charge the watch too often.

    Importance: HIGH

    Good value: >=35 h

    N/A
    Battery power
    What it is: The battery capacity, usually measured in milliampere-hours (mAh).
    When it matters: When you do not want to charge the watch too often.

    Importance: HIGH

    Good value: >=397 mAh

    230 mAh
    Haylou RS4 has a battery capacity of 230 mAh which is smaller than the batteries in 77% of smartwatches and equal to those in 1.9% of smartwatches.
    Charge time
    What it is: The time needed to recharge the battery from empty to full or to a stated percentage.
    When it matters: When you want to top up the battery quickly.

    Importance: HIGH

    Good value: <=102 min

    ?
    Show more
    Operating system
    What it is: The software platform that runs the watch interface, apps, and core functions.
    When it matters: When you care about apps, features, and long-term support.

    Importance: HIGH

    Proprietary OS
    Haylou RS4 runs Proprietary OS which is less advanced than the operating system in 53.6% of smartwatches and the same as that in 42.7% of smartwatches.
    Uses a proprietary OS with companion-app ecosystem support. OS detail: Proprietary OS (RTOS).
    Software update frequency
    What it is: Shows how actively the watch is still updated: regular means ongoing updates throughout active support, occasional means updates every few months or only from time to time, and ended means active software support has mostly stopped.
    When it matters: When you care how actively the watch is still supported with fixes, patches, and new features.

    Importance: MEDIUM

    ?
    Third-party app support
    What it is: Support for installing or using apps from developers beyond the watch maker.
    When it matters: When you care about apps, features, and long-term support.

    Importance: MEDIUM

    no
    Haylou RS4 does not support third-party apps. 47.6% of smartwatches support third-party apps.
    Notifications
    What it is: Mirroring of calls, messages, apps, or other alerts on the watch.
    When it matters: When you want to check alerts without taking out your phone.

    Importance: MEDIUM

    yes
    Haylou RS4 supports notifications. 99.9% of smartwatches support notifications.
    Voice assistant support
    What it is: Support for a voice assistant that can answer queries or trigger actions from the wrist.
    When it matters: When you want to control the watch or reply without typing.

    Importance: MEDIUM

    no
    Haylou RS4 does not support voice assistants. 68% of smartwatches support voice assistants.
    Show more
    Cellular module
    What it is: Built-in mobile connectivity that can keep the watch online away from the phone.
    When it matters: When you want calls, messages, or data without your phone nearby.

    Importance: HIGH

    no
    Haylou RS4 does not include a cellular module. 17.2% of smartwatches include a cellular module.
    SIM cards
    What it is: The number or type of SIM options the watch accepts for cellular service.
    When it matters: When you want calls, messages, or data without your phone nearby.

    Importance: LOW

    Good value: eSIM support

    0
    GPS
    What it is: Built-in satellite positioning that lets the watch record location during outdoor activity.
    When it matters: When you run, ride, hike, or navigate without relying on your phone.

    Importance: HIGH

    no
    Haylou RS4 does not support GPS. 56.1% of smartwatches support GPS.
    GPS works only via connected smartphone (no built-in GPS chip).
    Galileo support
    What it is: Support for Galileo satellites alongside other positioning systems.
    When it matters: When you run, ride, hike, or navigate without relying on your phone.

    Importance: MEDIUM

    no
    Haylou RS4 does not support Galileo navigation. 38.7% of smartwatches support Galileo navigation.
    Compass
    What it is: A directional sensor that helps the watch determine heading and orientation.
    When it matters: When you run, ride, hike, or navigate without relying on your phone.

    Importance: MEDIUM

    no
    Haylou RS4 does not include a compass. 49.3% of smartwatches include a compass.
    Show more
    Screen size
    What it is: The diagonal measurement of the visible display area, usually expressed in inches.
    When it matters: When you want the screen to be easy to read at a glance.

    Importance: HIGH

    Good value: >=1.5 inch

    1.78 inch
    Haylou RS4 has a screen size of 1.78 inch which is larger than the screens of 85.5% of smartwatches and equal to those of 2.9% of smartwatches.
    Display type
    What it is: The screen technology used by the watch, such as AMOLED, OLED, or memory-in-pixel LCD.
    When it matters: When you want the screen to be easy to read at a glance.

    Importance: HIGH

    AMOLED
    Haylou RS4 uses a AMOLED display type which is more advanced than that of 48.8% of smartwatches and the same as that of 51.3% of smartwatches.
    Resolution
    What it is: The total number of pixels available on the watch display.
    When it matters: When you want the screen to be easy to read at a glance.

    Importance: MEDIUM

    Good value: >=416 x 416

    368 x 448
    Haylou RS4 has a display resolution of 368 x 448 which is higher than that of 57.2% of smartwatches and equal to that of 2.7% of smartwatches.
    Pixel density
    What it is: The number of pixels packed into each inch of the display.
    When it matters: When you want the screen to be easy to read at a glance.

    Importance: MEDIUM

    Good value: >=326 ppi

    326 ppi
    Haylou RS4 has a pixel density of 326 ppi which is higher than that of 46.4% of smartwatches and equal to that of 8.3% of smartwatches.
    Display brightness
    What it is: The peak brightness the display can reach, usually expressed in nits.
    When it matters: When you want the screen to stay readable outdoors and in strong sunlight.

    Importance: HIGH

    Good value: >=1000 nits

    ?
    Show more
    CPU speed
    What it is: The clock speed of the watch processor, usually expressed in GHz or MHz.
    When it matters: When you want apps and menus to feel smooth.

    Importance: MEDIUM

    Good value: Modern standard

    ?
    Processor model
    What it is: The processor model is the chipset or SoC that powers the watch's performance, connectivity, and efficiency.
    When it matters: When you care about app responsiveness, platform generation, and long-term feature support.

    Importance: LOW

    Good value: modern smartwatch chipset

    ?
    RAM
    What it is: The amount of working memory available for apps, watch faces, and background tasks.
    When it matters: When you want apps and menus to feel smooth.

    Importance: MEDIUM

    Good value: >=1 GB

    ?
    Internal storage
    What it is: Built-in storage for apps, music, watch faces, and other local data.
    When it matters: When you want more room for apps, music, or offline data.

    Importance: MEDIUM

    Good value: >=8 GB

    ?
    External memory slot
    What it is: A slot for expandable storage such as a memory card, if the watch provides one.
    When it matters: When you want more room for apps, music, or offline data.

    Importance: LOW

    no
    Haylou RS4 does not include an external memory slot. 0.3% of smartwatches include an external memory slot.
    Show more

    Haylou RS4 vs the average smartwatch

    • 0.38 inch larger screen size
      Haylou RS4 has a larger screen size than the average smartwatch (1.8 inch vs 1.40 inch). The average smartwatch screen is 1.40 inch.
      What it is: The diagonal measurement of the visible display area, usually expressed in inches.
      When it matters: When you want the screen to be easy to read at a glance.

      Importance: HIGH

      Good value: >=1.5 inch

      Haylou RS4 has a larger screen size than the average smartwatch (1.8 inch vs 1.40 inch). The average smartwatch screen is 1.40 inch.1.78 inch vs 1.40 inch
    • Supports Wi-Fi
      Haylou RS4 supports Wi-Fi, the average smartwatch does not. 43.4% of smartwatches support Wi-Fi.
      What it is: Built-in Wi-Fi that lets the watch connect to wireless networks directly.
      When it matters: When you want the watch to work smoothly with your phone and accessories.

      Importance: MEDIUM

      Haylou RS4 supports Wi-Fi, the average smartwatch does not. 43.4% of smartwatches support Wi-Fi.
    • 3 day/s longer battery life
      Haylou RS4 offers 10 day/s of battery life, while the average smartwatch offers 7 day/s.
      What it is: The typical endurance the watch can deliver on a full charge under the stated usage pattern.
      When it matters: When you do not want to charge the watch too often.

      Importance: HIGH

      Good value: >=7 days

      Haylou RS4 offers 10 day/s of battery life, while the average smartwatch offers 7 day/s.10 day/s vs 7 day/s
    • Has weight tracking
      Haylou RS4 supports weight tracking, the average smartwatch does not. 39.2% of smartwatches support weight tracking.
      Tracked through the companion app or smart-scale sync.
      What it is: Logging or syncing of body-weight records over time.
      When it matters: When you want health data from your wrist during the day or night.

      Importance: LOW

      Haylou RS4 supports weight tracking, the average smartwatch does not. 39.2% of smartwatches support weight tracking.
    • Newer Bluetooth version
      Haylou RS4 supports a newer Bluetooth version than the average smartwatch (5.1 vs 5.0). The average smartwatch uses 5.0.
      What it is: The Bluetooth standard supported for pairing with phones, earbuds, and sensors.
      When it matters: When you want the watch to work smoothly with your phone and accessories.

      Importance: MEDIUM

      Good value: >=5.1

      Haylou RS4 supports a newer Bluetooth version than the average smartwatch (5.1 vs 5.0). The average smartwatch uses 5.0.5.1 vs 5.0
    • 2.89x cheaper
      Haylou RS4 is cheaper than the average smartwatch (£45 vs £130).
      Haylou RS4 is cheaper than the average smartwatch (£45 vs £130).£45 vs £130
    • Has weight tracking
      Haylou RS4 supports weight tracking, the average smartwatch does not. 39.2% of smartwatches support weight tracking.
    • 3 day/s longer battery life
      Haylou RS4 offers 10 day/s of battery life, while the average smartwatch offers 7 day/s.
    • Supports Wi-Fi
      Haylou RS4 supports Wi-Fi, the average smartwatch does not. 43.4% of smartwatches support Wi-Fi.
    • Newer Bluetooth version
      Haylou RS4 supports a newer Bluetooth version than the average smartwatch (5.1 vs 5.0). The average smartwatch uses 5.0.
    • 0.38 inch larger screen size
      Haylou RS4 has a larger screen size than the average smartwatch (1.8 inch vs 1.40 inch). The average smartwatch screen is 1.40 inch.
    • No smart scales
      Haylou RS4 does not support smart scale compatibility, the average smartwatch does. 56.8% of smartwatches support smart scale compatibility.
    • No elevation tracking
      Haylou RS4 does not support elevation tracking, the average smartwatch does. 62.7% of smartwatches support elevation tracking.
    • No gyroscope
      Haylou RS4 does not include a gyroscope, the average smartwatch does. 64.6% of smartwatches include a gyroscope.
    • No pace measurement
      Haylou RS4 does not support pace tracking, the average smartwatch does. 78% of smartwatches support pace tracking.
    • No coaching
      Haylou RS4 does not support coaching, the average smartwatch does. 51.8% of smartwatches support coaching.
    • No swim mode
      Haylou RS4 does not include a swim sport mode, the average smartwatch does. 74.9% of smartwatches include a swim sport mode.
    • No routes
      Haylou RS4 does not support route support, the average smartwatch does. 50.4% of smartwatches support route support.
    • No voice feedback
      Haylou RS4 does not support voice feedback, the average smartwatch does. 62.1% of smartwatches support voice feedback.
    • 68 fewer exercise profiles
      Haylou RS4 supports fewer exercise modes than the average smartwatch (12 vs 80). The average smartwatch supports 80 exercise modes.
    • 70 mAh smaller battery capacity
      Haylou RS4 has a smaller battery capacity than the average smartwatch (230 mAh vs 300 mAh). The average smartwatch battery is 300 mAh.
    • No GPS
      Haylou RS4 does not support GPS, the average smartwatch does. 56.1% of smartwatches support GPS.
      GPS works only via connected smartphone (no built-in GPS chip).
    • No always-on display
      Haylou RS4 does not have an always-on display, the average smartwatch does. 66.4% of smartwatches have an always-on display.
    • 48.5 m lower waterproof depth
      Haylou RS4 has a shallower waterproof rating than the average smartwatch (1.5 m vs 50 m). The average smartwatch reaches 50 m.
      Based on IP immersion rating (controlled lab conditions, not a swim/diving certification).
    • No ambient light sensor
      Haylou RS4 does not include an ambient light sensor, the average smartwatch does. 60.5% of smartwatches include an ambient light sensor.
    • No music playback
      Haylou RS4 does not support music playback, the average smartwatch does. 53.9% of smartwatches support music playback.
    • No call answering
      Haylou RS4 does not support call answering, the average smartwatch does. 57% of smartwatches support call answering.
    • No voice commands
      Haylou RS4 does not support voice commands, the average smartwatch does. 64.5% of smartwatches support voice commands.
    • No voice assistant
      Haylou RS4 does not support voice assistants, the average smartwatch does. 68% of smartwatches support voice assistants.
    • No gesture control
      Haylou RS4 does not support gesture control, the average smartwatch does. 78.1% of smartwatches support gesture control.
    • No widgets
      Haylou RS4 does not support widgets, the average smartwatch does. 83.1% of smartwatches support widgets.
    • No speaker
      Haylou RS4 does not include a built-in speaker, the average smartwatch does. 54.7% of smartwatches include a built-in speaker.
    • 1 fewer microphones
      Haylou RS4 has fewer microphones than the average smartwatch (0 vs 1). The average smartwatch includes 1 microphones.
    • No GPS
      Haylou RS4 does not support GPS, the average smartwatch does. 56.1% of smartwatches support GPS.
      GPS works only via connected smartphone (no built-in GPS chip).
      What it is: Built-in satellite positioning that lets the watch record location during outdoor activity.
      When it matters: When you run, ride, hike, or navigate without relying on your phone.

      Importance: HIGH

      Haylou RS4 does not support GPS, the average smartwatch does. 56.1% of smartwatches support GPS.
    • 48.5 m lower waterproof depth
      Haylou RS4 has a shallower waterproof rating than the average smartwatch (1.5 m vs 50 m). The average smartwatch reaches 50 m.
      Based on IP immersion rating (controlled lab conditions, not a swim/diving certification).
      What it is: The stated depth or water-resistance class the watch is rated to withstand.
      When it matters: When you wear the watch in rain, sweat, or water.

      Importance: HIGH

      Good value: >=50 m

      Haylou RS4 has a shallower waterproof rating than the average smartwatch (1.5 m vs 50 m). The average smartwatch reaches 50 m.1.5 m vs 50 m
    • No always-on display
      Haylou RS4 does not have an always-on display, the average smartwatch does. 66.4% of smartwatches have an always-on display.
      What it is: A display mode that keeps key information visible even when the watch is idle.
      When it matters: When you want the screen to be easy to read at a glance.

      Importance: HIGH

      Haylou RS4 does not have an always-on display, the average smartwatch does. 66.4% of smartwatches have an always-on display.
    • No speaker
      Haylou RS4 does not include a built-in speaker, the average smartwatch does. 54.7% of smartwatches include a built-in speaker.
      What it is: An onboard speaker for calls, prompts, alarms, or media playback.
      When it matters: When you want audio, calls, or voice features on the watch itself.

      Importance: LOW

      Haylou RS4 does not include a built-in speaker, the average smartwatch does. 54.7% of smartwatches include a built-in speaker.
    • No elevation tracking
      Haylou RS4 does not support elevation tracking, the average smartwatch does. 62.7% of smartwatches support elevation tracking.
      What it is: Tracking of climbed, descended, or current elevation during activities.
      When it matters: When you run, ride, hike, or navigate without relying on your phone.

      Importance: MEDIUM

      Haylou RS4 does not support elevation tracking, the average smartwatch does. 62.7% of smartwatches support elevation tracking.
    • No music playback
      Haylou RS4 does not support music playback, the average smartwatch does. 53.9% of smartwatches support music playback.
      What it is: Playback of music or audio directly from the watch, with or without a phone nearby.
      When it matters: When you want audio, calls, or voice features on the watch itself.

      Importance: MEDIUM

      Haylou RS4 does not support music playback, the average smartwatch does. 53.9% of smartwatches support music playback.
    • No gyroscope
      Haylou RS4 does not include a gyroscope, the average smartwatch does. 64.6% of smartwatches include a gyroscope.
      What it is: A motion sensor that measures rotation and helps interpret wrist movement more accurately.
      When it matters: When you track workouts and want better training data.

      Importance: MEDIUM

      Haylou RS4 does not include a gyroscope, the average smartwatch does. 64.6% of smartwatches include a gyroscope.
    • No pace measurement
      Haylou RS4 does not support pace tracking, the average smartwatch does. 78% of smartwatches support pace tracking.
      What it is: Tracking of current or average pace during activities such as running or cycling.
      When it matters: When you track workouts and want better training data.

      Importance: MEDIUM

      Haylou RS4 does not support pace tracking, the average smartwatch does. 78% of smartwatches support pace tracking.

    Graphic comparison of Haylou RS4 and other Smartwatches

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    Third-party reviews

    (Reviews last updated: Apr 2026)

    What customers like about Haylou RS4?

    • Vibrant 1.78-inch AMOLED display with high resolution (368x448)
    • Extremely affordable price point for an AMOLED wearable
    • Sleek, minimalist design with a high-quality metal frame
    • Lightweight and comfortable for all-day wear
    • Good battery life, typically lasting 10+ days on a single charge
    • IP68 dust and water resistance
    • Smooth and responsive user interface performance

    What customers dislike about Haylou RS4?

    • Lack of built-in GPS (relies on connected smartphone for tracking)
    • Haylou Fun companion app is reported to be buggy and poorly implemented
    • No built-in microphone or speaker for Bluetooth calls
    • Limited to a small number of built-in workout modes (only 12)
    • Poor legibility for notifications due to unflattering font and spacing
    • Inaccurate SpO2 sensor readings compared to medical-grade devices
    • Wireless payments are limited to Alipay, which is not useful in Western markets

    Video reviews

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