Honeywell Howard Leight™ Impact® Pro Industrial Earmuff The Howard Leight™ Impact® Pro Industrial earmuff has the highest passive NNR (30 NRR) in electronic earmuffs on the market. The Impact Pro Industrial is built to protect worker's hearing while allowing them to have environmental awareness. The Impact Pro Industrial has strategically placed directional stereo microphones to amplify ambient sounds, including alarms/warning, signals, and conversations while suppressing loud, impact noises down to a safe level of 82dB. The newly designed "textile" headband with extra cushion offers all day comfort. The Impact Pro Industrial also has audio jack connection capabilities to pair up with a personal listening device.