M 4 fitness smart band: If you're a fitness freak and love keeping a track of the calories burnt, sleep cycle, and heart rate, and then the M 4 Smart Band is what you need. This smart band works as a heart rate tracker, fitness watch, and an activity tracker. It is compatible to devices having Bluetooth version 4.0 and below in smart phones, Tablets and PC's and also support Android and i OS. It has features such as calling function which enables you make a phone and disconnect it, you can also send and receive messages through it but only supported to android Phones for which you need to download app.Functions:1.Heart rate monitor2.Sedentary reminder3.Calories4.Time5.Alarm6.Anti-lost7.Distance calculation8.Step Monitor10.Phone alert11.Wrist sensePre-requisites for use: Your mobile phone Bluetooth version must be Bluetooth 4.0 or higher, iOS version must be iOS 7.1 or above, Android version must be Android 4.3 or above.Working: To connect the smart band to mobile phone, you need to connect the current mobile successfully via Bluetooth. Press unbind icon and band has been successfully connected with the device.Specifications HR sensor :Silicon labs S i 1142, host weight : 7g, battery type: rechargeable Li battery, battery capacity: 40 mAh, data sync: Bluetooth 4.0, working temperature :- 10 c to 50 c, waterproof : not for swimming or diving, standby time : 15 days and above. This product uses professional bluetooth RF signal and custom algorithm, the accuracy can reach 100% and above Package Contents: 1 x bluetooth smart bracelet 1 x user manual 1 x USB charging cable Note: When the band needs to be bind to another mobile, it needs to be tied the current mobile phone first.