NEW Stanley Sync Digital Am/fm/mp3 Radio Noise Reduction Earmuffs Headphones Noise Reduction Rating (NRR) 25 provides ideal hearing protection in moderate noise environments Hearing protector for use with MP3 players, mobile phones and other personal listening devices Volume Management Technology manages sound levels reaching the user's ear to a safe level High-fidelity sound quality is on par with professional headphones Technologically advanced acoustical bass chamber (patent pending) enhances bass sounds that are typically sacrificed in a stereo earmuff