Pro Ears - Pro 300 - Electronic Hearing Protection and Amplification - NRR 26 - Ear  Muffs Pre-set at 15 decibels of amplification. Versatile use cup design. Pro Form Leather ultra comfortable ears seals, and padded adjustable headband. Weighs only 9.1 ounces. Attack time of 5.5 milliseconds. Includes 4 N size batteries. Battery life is 300 hours. Weighs only 9.1 ounces. Attack time of 5.5 milliseconds. Includes 4 N size batteries. Battery life is 300 hours.