Most stereo earmuffs used in industry today provide a moderate level of hearing protection, but often sacrifice the sound quality of the attached MP3 players.

Not the Sync Stereo from Howard Leight.
Featuring an optimised new design and technology that provides both hearing protection and a true quality listening enjoyment.
With an SLC80 rating of 31dB Class 5, Sync Stero provides ideal, consistent hearing protection and ensures appropriate attenuation in most industrial environments. Sync’s Volume Management Technology™ manages sound levels reaching the user’s ear to a safe level.
There are no volume knobs or power switches to coordinate nor batteries to replace. Ease-of-use is enhanced by maintaining volume and power control through the MP3 device. Users simply plug MP3 players and personal audio devices and listen.