The Razor Slim Electronic Muff operates on two AAA batteries (included). Protect your hearing from loud noise with the Walkers Razor Slim Electronic Muff. This muff features two omnidirectional microphones to assure that you don't miss anything and get crisp clear audio Delivering an impressive Noise Reduction Rating (NRR) of 23 dB, this muff is sure to protect your hearing, without interfering. It features comfort fit headband with metal wire frame for all day shooting, with a slim and compact folding design that takes up less space in your bag.