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Black chest-strap heart-rate sensor with 1.04" front display and adjustable 64-86cm elastic band

4iiii Innovations H64 wearable technology 1.04" 1000h 64-86cm IP67

SKU CH-NFXZ-9W7JF MPN H64

Heart-rate chest strap with ANT+ and Bluetooth, 1000-hour battery, adjustable 64-86 cm strap, IP67 water resistance

  • Screen size1.04 in (2.64 cm)
  • SizeLarge
  • Supported platformsAndroid
  • Run time1,000 h
  • Standby duration1,000 h
  • Spec summaryH303, Magene, 0.059 kg, 1,000 h, lithium manganese dioxide,
  • Accurate heart-rate tracking via new hardware and algorithms
  • LED flashes to confirm heart-rate and connection status
  • Simultaneous ANT+ and Bluetooth recording for one workout
  • Adjustable chest strap fits 64 to 86 cm
  • IP67 water resistance for sweat and rain protection

Heart Rate Sensor Chest Strap

The H303 heart rate monitor is a wearable sensor designed for athletes who want accurate cardiac data during training. It transmits simultaneously over ANT+ and Bluetooth to compatible apps and devices. The unit weighs 0.059 kilograms and includes a pre-installed CR2032 battery. It suits cyclists, runners and team-sport players who need reliable real-time feedback.

Upgrade From Optical Wrist Sensors

Chest-strap placement eliminates the motion artefacts and sweat interference that degrade wrist-based optical readings during high-intensity intervals. The new hardware and algorithms filter noise caused by movement and perspiration. The jump is worth it when interval precision dictates pacing decisions or when a coach requires clean ANT+ logs for post-session analysis. Optical wrist units remain adequate for steady-state zone checks.

Snap-On Module With Adjustable Strap

The sensor module clips onto the supplied elastic strap, which adjusts from 64 to 86 centimetres. Pairing is automatic once the strap contacts skin; the front LED flashes ten times to confirm connection. Common issues include a loose strap that breaks skin contact during vigorous movement and forgetting to wet the electrodes before cold-weather sessions. The module is IP67 rated for splashes and rain but not for swimming.

How it compares

Measured against everything we stock in Smartwatches & Wearables, at today’s prices. Recalculated every night.

Price $38.99
Cheaper than about 60% of the 2,527 comparable items (median $44.99).
Screen size 1.04 in (2.64 cm)
Lower than about 70% of the 228 comparable items (median 1.4 in).

Specifications

Product
Brand name4iiii Innovations
Model nameH303
Part numberH303
Product colorBlack
Display
Screen size1.04 in (2.64 cm)
Power
Run time1,000 h
Standby duration1,000 h
Size & build
SizeLarge
Overall height2.45 L x 1.38 W x 0.45 H inches
Product depth6.23 L x 3.51 W x 1.15 H centimeters, 2.45 L x 1.38 W x 0.45 H inches
Product weight0.059 kg
Compatibility
Supported platformsAndroid

Questions about this item

What chest circumference does the adjustable elastic strap cover?

The elastic strap adjusts from 64 to 86 centimetres, fitting most adult torsos.

How do I pair the sensor and what common step causes connection failure?

Wet the electrode pads, snap the module onto the strap, then pair via ANT+ or Bluetooth in your app; skipping the wetting step is the usual cause of no signal.

When and how do I replace the power source?

After roughly 1000 hours of use, remove the module, pry out the CR2032 coin cell, insert a fresh one with the positive side up, and reseal the cover.

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