SportEar XT4 Electronic Head Muff (Black) Chop-side cups for easy Use with rifles 25 dB noise reduction rating Automatically stops all sound over 85 dB Adjustable frequency knobs Four Directional mics to enhance hearing Automatically shuts out sounds over 85 dB./ 27 dB Noise reduction rating (NRR) Adjustable frequency knob Sleek cup for comfort On/Off volume control