General Aircraft Adjustable Metal Boom with 360 Degree Rotational for Left or Right Side OVER-THE-HEAD STYLE Noise Reduction Ratings (NRR):29dB HOW TO PUT THE BATTERY ♦ GA use dual plugs. ♦ Active Noise Reduction Ratings(NRR):29dB. ♦ Passive Noise Reduction Ratings(NRR):23dB. ♦ Small AA battery box with belt clip.(Battery not include) ♦ Comfortable half gel half foam ear pad. ♦ Clear Hear performance audio speakers. ♦ Noise-canceling electret Microphone, dynamic microphone can be replaced. ♦ Fully adjustable spring steel headband ♦ Low-profile volume control knob. ♦ Earphone Plug: PJ-055(.25"F6.3 phone plug). ♦ Microphone Plug: PJ-068(.206"F5.2 phone plug). ♦ Straight cord from headset to molded plug, 150CM. ♦ Colors:Black,Blue,Yellow,Green,Gray,Pink,Red.