Allows for continuous communication on 2-ways even when batteries fail; only talk-thru is unavailable until battery replacement. • Instantly suppresses harmful impact noises to 82dBA inside earcups. • Amplifies up to 18dB ambient noises/voices. • Electronic headset for military applications, requires 2 AA batteries for 270 hours of life. • Fits under PASGT, MICH and ACH helmets