Trusted leaders in hearing protection, Walker's is a 30 year brand preferred by the professional and occasional user alike. The Razor Slim Profile muff design features a nonintrusive comfortable fit for all day use. Sound amplification allows better enviromental awareness whether at a work site, recreational event or shooting/hunting outing. Razors feature omni directional microphones, full dynamic range HD speakers and volume control with on/off easy to adjust traction knob, as well as 0.02 second sound activated compression for any damaging deibels and 23NRR rating. With a comfortable, strong wire band and audio input jack, it runs on 2 "AA" betteries, which are included. Designed and engineered in the USA.