Elvex Impulse (R-Com-655) electronic earmuff allows you to eliminate impulse sounds such as gun fire electronically and still hear the shooting instructor or game at up to 10 dB amplification. Two outside microphones send sound through processor. Eliminate impulse sounds such as gun fire electronically. Circuitry closes down in milliseconds and reactivates in about 1/4 of a second. An audio jack (3.5 mm jack) for connection of auxiliary devices is standard. This input will allow listen only capability, not two way communication. Two AAA batteries power the headset for approximately 175 hours. Batteries are included and are accessed through an outside battery compartment.