Microphones amplify range commands and conversation in stereo up to four times, while Air Flow Control™ technology protects ears from sounds above 82db. Rugged earcups are made of durable rubber. Padded headband is adjustable for a comfortable fit. Single knob controls on/off and volume. Four-hour automatic shut-off. Includes audio jack and input cord for MP3 players, smartphones and scanner radios. Uses two AAA batteries (included).