1" Display128 X 128p Backlight For Dark Conditions Watch Mode & Activity Mode Convenient Low-profile Design For Ease & Style Watch Mode Activity Mode Connects To A Smartphone Or Device With Bluetooth Connectivity To Stream Information & Data & Control Apps Tracks Steps Distance Calories Burned & Sleep Length & Pattern Water-resistant (ipx7) Ruggedized For Sports Compatible With Iphone 4s Or Later & Select Android Devices With 4.4 Or Later Compatible With Many Leading Fitness Apps Including Strava Mapmyrun Mapmyride Wahoo Fitness & More Ultralow Power Consumptionnever Requires Recharging 6-month Battery Life On Heavy Usage 11-month Battery Life On Low Usage Requires A 3v Cr2032 Battery Blue