Pro Ears - Pro Slim Gold - Electronic Hearing Protection and Amplification - NRR 28 - Ear Muffs - Black Military grade dual circuit boards. NRR 28 Gold Connectors for high quality audiophile sound. Automatic shut off after 4 hours Pro Form Leather ultra-comfortable ears seals, and padded, adjustable headband. Amplifies sound more than 8x Weighs only 11.1 ounces. Fast attack time of 1.5 milliseconds. Includes batteries. 3.5mm input jacks for i-pod and MP3 players. Battery life is 250 hours. Five (5) Year Warranty Made in the USA