Caldwell EMax Electronic Hearing Protection 497700Standard profile E-MaxTM hearing protection combines great circuitry with a standard earcup for better protection. The two microphones in the E-MaxTM amplify sounds below 85 decibels, which amplifies normal communication, range commands, and environmental sounds. Above 85 decibels, the microphones shut off for a split second to protect the shooter's hearing.Two microphones - one in each cup - give the user true stereo sound and allow the user to identify the directional source of a sound.