This model from Peltor incorporates a new ASIC chip technology for clearer, cleaner, and more refined audio. The loud impulse noise shut-down is lightning fast, but so gentle you will hardly notice the shut-down. These muffs are comfortable for all day wear, amplify ambient sound, have an auto shut-off after two hours and include easily changeable (external compartment) AAA Alkaline batteries. The ear cups are ergonomically designed for comfort and the cups are contoured for a good rifle stock weld. Interchangeable orange and black ear cup covers are included with a micro fiber storage/carry bag. These muffs also include an audio input port for cell phones, field radios, and MP3 players. NRR Rating is 20 dB. Made in U.S.A., designed in Sweden.
Big Book Catalog, Issue:69, Page:359
Sinclair, Issue:5B, Page:222