The CaldwellA(R) E-MaxA(R) hearing protection combines great circuitry with a standard earcup for better protection. The two microphones in the E-Max amplify sounds below 85 decibels, which amplifies normal communication, range commands, and environmental sounds. Above 85 decibels, the microphones shut off to protect the shooter's hearing. Ear cup width is 1.75 inches and two AAA batteries are required but not included. Enabled with one stereo microphone in each cup, the user can localize sound from all directions. 25dB Noise Reduction Rating.