The latest in HD sound technology offers you incredible sound reproduction without all the noise and distortion. Wind noise reduction is superior to other devices and the noise reduction rating of 29 decibles is among the highest in the industry. The unit has 48 dB of power with a pre set high frequency response circuit, with emphasis on high frequency sounds. It also includes a sound activated compression circuit that when combined with the ear plug design protects hearing from loud sounds when working around loud eqipment. Each lightweight, ergonomic unit weighs less than 1/4 ounce, so it wears comfortably behind the ear even when wearing glasses. Includes a #13 battery.