CLEARER SOUND. DEEPER BASS. MiiSport C headphones are the only MiiKey headphones that come with sweat proof speakers inside each ear. That means you get crystal clear highs and deep, rumbling lows in high definition. Features: Bluetooth 4.0 wireless connection Voice prompt lets you know MiiSport C"s status Battery merit on your phone to know battery -connect Built-in microphone for calls Long-lasting built-in Li-Ion battery Sweat-proof Smart Talk works with Apple"s stereo sound Compatible with any Bluetooth device Specifications: Bluetooth version: Version 4.0 + EDR Operation distance: 33 feet. Range of frequency: 2.4 to 2.483 -in Li-Ion battery 300 mAh. Built-in microphone. What"s in The Box: MiiSport C Bluetooth headset. USB charging cable. User"s guide.