Elvex Plug-in™ Receiver Muff. Elvex Plug-in Com ear muff can be connected to Com radios, MP3 players, CD players, FM radios and similar devices, if they are equipped with an output jack for a 3.5 mm plug. The headset is equipped with a coiled cord with a 3.5 mm plug. You will hear the sound from your device, loud and clear, up to the maximum sound level allowed by the specific Plug-in model. Features of Elvex Plug-in: 25 dB NRR from certified U.S. Laboratory to ANSI S3.19-1974 . Connects via 3.5 mm plug to Com radios, CD player and more . The headset is equipped with a volume control knob, allowing the user to easily adjust the volume at the headset. Excellent sound quality for both music and voice communications. Electronic limiter set at 85 dB for compliance with OSHA requirements.