Bilsom® Radio Hi-Visibility earmuffs feature a 3.5mm AUX input jack, allowing the earmuff to connect to MP3 players and other portable audio devices. Bright green earcups and reflective headband provide clear visibility, day or night. Patented Air Flow Control™ technology provides optimal attenuation across all frequencies when radio is off.Bacou-Dalloz Hearing Safety Group,, (800) 430-5490