Note:Transmitter: Attach it to the strap in the right directions.Battery: Open and close it with a coin.Features: 1. Being a sensor type heart rate monitor， it will detect and send your real-time heart rate to the smart phone accurately.2. With the chest strap based on high quality material， it can be attached to your skin closely.3. Ultra low power consumption， a CR2032 battery， is replaceable and will last up to 1 year.4. Works with running， cycling， walking and so on.5. Adjustable chest strapSpecifications:Color: BlackBattery: 1X CR2032Material: ABS+plastic+silica gelTechnology:  Bluetooth 4.0LE(Low energy)Transmission:  Wireless BluetoothSupport Device: iPhone 4S/5/5S/5C/6/6 Plus/iPod Touch/iPad/iPad  3 4 Mini Air & Android 4.3 or Newer Devices with Bluetooth 4.0 Package Include: 1X Bluetooth 4.0 Heart Rate Monitor Chest Belt