Bluedio 1566998 H Plus Turbine Wireless Bluetooth 4.1 Stereo Headphones with Mic/Micro SD Card Slot/FM Radio, Black Bluedio 57mm dynamic drivers let you feel the powerful bass in your tunes Cool look inspired from turbine which we think can best represent your endless energy Up to 40 hours of music time from the latest Bluetooth 4.1 low-power technology Support FM broadcast / micro SD card playback of MP3 and WAV audio formats, note: micro SD card not provided Simply plug in the audio cable when the battery runs low or connecting to non Bluetooth devices