Features:Professional-Quality Hearing Protection (23dB NRR)Environmental microphones for level-dependent hearing protection and ambient listening3.5 mm listen-only stereo input for connection to external devices (e.g. cell phone, two-way radio, Ipod)Voice guided menu system for ease of use and adjusting settingsAuto power off, the headset will turn off after 4 hrs of non-use to save batteryLow-battery warning to inform you when to change batteriesTo reduce corrosion caused by sweat and moisture, the electronics are located in a separate compartment of the cupAvailable in both in headband and hard hat attached versions (black)Occupational use onlyEnvironmental microphones for level-dependent hearing protection and ambient listening3.5 mm listen only stereo input for connection to external devices (Smartphones, shoulder microphones, etc.)Voice guided menu systemAuto power off: The headset will turn off after 4 hrs of non-use to save batteryLow-battery warning.To reduce the corrosion caused by sweat and moisture, the electronics are located in the outer part of the cup21dB NRR; occupational use onlyThe ProTac III hearing protector helps protect against hazardous and nuisance noise, while allowing environmental sounds to be reproduced by the electronic circuit, limited to 82dB. ProTac III helps protect hearing from impulse noise and increases the ability to communicate with nearby colleagues, as well as hear warning signals, approaching vehicles, and sounds in machines and processes.A great value in electronic level-dependent hearing protection, 3M™ PELTOR™ is a leading brand in electronic level-dependent hearing protection for professionals who have an occupational exposure to steady state or impulse noise. The ProTac III helps protect workers' hearing and allows them to listen to important ambient sounds (at a maximum level of 82dB), allows them to communicate with colleagues, hear warning signals and approaching hazards, while protecting their hearing.