Toprime Fitness Tracker, Waterproof Activity Sport Tracker Smart Watch with Sleep Monitor Pedometer Calories Counter for iOS and Andriod Functional:Tracks steps,distance,calorie burned,sleep monitor(deep/light sleep).notification from SMS message,app message(Facebook,Twitter,Whatsapp,etc), caller ID and alarm.Water resistant IP65 and accurate. Soft Material: Made out of durable and safe silicone,which is smooth and harmless when contacting your skin,strap diameter 2.16--2.76 inch fits all wrist. Compatibility: Support smart device with Android 4.4 / iOS 7.0 or above, Bluetooth 4.0 or above. Download APP "Zeroner Health" from Apple Store or Google Play. Easy to charge,plug into USB port to charging (laptop,USB station,PC and more) and full charge with standby time for 7 days and more. Any questions please contact us first,we will help you solve your problems,replacement or refund