GBH-M300 Mono Bluetooth Headset Bluetooth Version 2.1 (Also compatbile with Version 2.0, 1.1 and 1.0). Supports headset and hands-free profiles Slim and stylish mono Bluetooth headset for call and detachableear-hook. Smart connection: Just slide up the lock button for incoming calls. It connects to call automatically DSP Included (Wind Noise Reduction, Echo reduction technology minimizes background noise and Automatic Volume Control) Ultra power save mode: Standby time up to 6 months at call lock position Call Lock: Prevent unintentional call by sliding lock button