Weight 18g Battery Life 20 hours of continuous heart rate monitoring on a single charge Wireless Bluetooth 5.0 & ANT+ Battery Type 90mAh Lithium Battery Operating Temperature 0°C ~ 40°C Size 46.5 x 36 x 14mm Brand new, unused, and unopened. This device is worn on the arm to measure heart rate during exercise. There are also chest strap types, but wearing it on the arm is much easier. Thank you.