The Pro 300 muff is the standard contoured model of Pro Ears electronic hearing protection. Designed with a Noise Reduction Rating (NRR) of 26, the Pro 300 protects your ears 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. The Pro series' amplification comes with the preset at 15 decibels. For the ultimate in Performance, Comfort and Reliability.