OPSMEN M31 Electronic Sound Amplifying Hearing Protector (Color: Coyote Brown)$$Other

Noise reduction rating + NRR22 3 levels electronic restoration of ambient sound Suppresses harmful noise above 82 dB while amplifying low-level sounds Different reminder tones of ON/OFF & restoration adjusting Power by 2xAAA batteries, approx. 350 hours of operation with new alkaline batteries, 4 hours auto shut-off mechanism Ergonomic designed cups provide super comfortable wearing & sealing (Anti-sweat with NANO technology)