The Pro Tac Slim muff is the premium model of Pro Ears. Designed with a Noise Reduction Rating (NRR) of 28, the Pro Tac Slims provide exceptional protection for the loudest environments while still amplifying quieter sounds for improved situational awareness. Constructed using dual circuit board technology, adjust your hearing and amplification levels separately for each ear to compensate for uneven hearing loss using the dual knob system. Additional adjustment for high and low gain using internal pin settings. For the ultimate in Performance, Comfort and Reliability.