Nuband Activ + Navy Activity and Sleep Tracker Band, Bluetooth Enabled App for Apple and Android - Blue Type: Fitness Band Color: Dark Blue Size: N/A Features: Time/Date; Tracks - steps, calories burned, distance traveled during day, % of goal achieved, and sleep activity during the night. Specification: BT 4.0 compatible with iOS 7.0 and Android version 4.3 and above Power Source: Built in rechargeable Li-on polymer battery Battery Life: 5 to 7 days Operating Environment: Nuband iOS/Android