The Howard Leight Impact Sport is an electronic earmuff with a sleek, low-profile ear cup design and an adjustable headband for a secure, non-slip fit. It automatically shuts off noise above 82 decibels. A single power and volume control knob allowing you to hear conversations near or far from you. To capture low level sound, the Impact Sport employs built-in microphones that amplify range commands and other important sounds. Users enjoy full, clear directional hearing in stereo. For protection, the Impact Sport actively listens and automatically shuts off amplification whenever harmful sound levels are reached. The earmuffs effectively block any noise, continuous or impulse, of 82 decibels or more. External audio input allows you to connect your mp3 player or other audio source. The Impact Sport boasts outstanding battery lifetime, running on 2 AAA batteries, included.