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.