HW9 equips with a 5-color LED, you’ll know exactly which zone you are in and when you’re in the zone now. This allows you to train efficiently and effectively, giving you the edge you need to take your performance to the next level. Try HW9 today and unlock your full potential! Body dimensions(LxWxH): 41.3×33.8×11 mm • Weight: 20g • Battery: Rechargeable lithium battery, 90 mAh • Battery Life: 35 hours • Wireless connections: Bluetooth5.0, ANT+ • HRV: Yes • LED indicator: Yes • Charging method: Magnetic USB Charging • Operating Temperature:-10℃~ 50℃