Radians R-3700 Bluetooth Quad Mic Electronic Earmuffs - Radians R-3700 Bluetooth Quad Mic is an electronic sound amplification earmuff featuring Bluetooth wireless technology. Four independent microphones provide a full surround sound experience that amplifies low sound level noises while compressing sounds that exceed safe levels. Compact folding feature for easy storage. Works wirelessly with most smart devices. Electronic compression to protect hearing Amplifies environmental sounds for enhanced hearing Four microphones Bluetooth connectivity compatible with most smart devices LED On / Off indicator light Adjustable headband folds for compact storage 3.5mm stereo input jack and patch cable enable playback from smartphone or digital audio player NRR 24 dB (2) two AAA batteries required