Originally designed for the military and for helicopter operations, the matt black PA17-79's ear cups are deeper in volume than it's predecessor (the PA17-76), thereby increasing passive noise attenuation. This headset has been updated with a more sophisticatedly designed electronics package using closer tolerance mil-spec components. The thing that makes this headset really quite unique is its built-in NiMH rechargeable batteries in the ear cups which means no battery box. Even with the batteries built-in this is an incredibly lightweight headset. Also Available in Helicopter configuration.