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