Optimizing acoustical earcup design, volume management technology and personal hearing protection, Honeywell Stereo Hearing Protector Earmuffs deliver proper levels of hearing protection in hazardous noise environments. These hearing protector earmuffs include high-fidelity stereo sound from a user's MP3 player, smart phone and other personal listening devices. They feature a stylish, DJ-inspired earcup design, sound quality equal to many professional and high-end personal stereo headphones and technology to manage output volume from portable audio devices at safer levels. The Sync includes a 3.5-millimeter input cable that plugs into most MP3 players, mobile phones and other personal audio devices.