The Impact enhances user awareness through advanced sound amplification technology. It allows wearers to hear important communication - other co-workers, alarms and warning signals - at a safely amplified level. Positioned microphones provide more natural, directional hearing. Through an advanced response technology, Impact reverts to passive earmuff mode when noise reaches 82 dB or above.Features : Amplifies Ambient Sound Reverts to Passive Hearing Protector When Noise Reaches 82 dB Stereo Microphones