Radians R-3200 Dual Mic is an electronic sound amplification earmuff. Two independent microphones pick up and amplify low sound level noises while compressing sounds that exceed safe levels. Compact folding feature for easy storage. 3.5mm stereo input jack and patch cable works with most smart devices.FeaturesElectronic compression to protect hearingAmplifies environmental sounds for enhanced hearingTwo microphonesLED On / Off indicator lightAdjustable headband folds for compact storage3.5mm stereo input jack and patch cable (included) enable playback from smartphone or digital audio playerNRR 23 dB2-AAA batteries required (not included)