W-inds Fitness Tracker Waterproof Wearable Pedometer Activity Tracker for Step Distance Calories Burning and Sleeping Quality Black Red Blue Purple Color Android 4.4 or above, iOS 7.0 or above, Bluetooth 4.0 or above required. Download APP "Zeroner" from Apple Store or Google Play for free. USB Charging and standby time will up to 5-7 days or more if fully charged. Fitness tacking for steps, distance, calorie burning & sleeping quality. Calling & SMS notification, Sedentary reminding, anti-lost. Removable light weighted wristbands with maximum wearable size 9 inches & minimum size 6.5 inches. Waterproof IP65. Ship from USA.