The built-in orienteering microphone can amplify the range instructions and other ambient sounds to a secure 82 dB, providing more natural listening and enhanced communications. Active monitoring and auto-close amplification when the ambient sound reaches 82 dB. With noise reduction level (NRR) of 22dB. Can be used for the cleaning of the gun stock Adjustable headband to ensure safety. Compact folding design is convenient for storage. Integrated power/ volume knob - Includes AUX input and 3.5 mm connecting cable for MP3 player and scanner. With auto power off function (when no operation after 4 hours) to extend battery life. Long battery capacity to play for about 350 hours. Specification: Type: Noise-proof Earmuff Product Weight: Approx. 1 lb Product size: Approx. 11 * 10 * 4CM(Single earplug) Battery type: 2 AAA batteries (NOT Included) Style: earmuffs Material: ABS plastic Energy-source: Battery powered Sound level: 24 dB Measurement System: English/ Standard Special function noise reduction level (NRR): 22 dB Usage: Passive protection Included component: Impact Sport earmuffs, 3.5 audio connections Whether include battery: NO Average battery life: about 350 hours Package list: 1 * Noise-proof Earmuff 1 * 3.5MM Audio Cable 1 * Instruction Manual Note: 1. Please note that it requires 2 AAA batteries, which are NOT included. 2. Please allow slight error due to manual measurement. Thanks for your kind understanding.