Oregon Aero SoftSeal®/HushKit® combo for the military HGU-56P Aviation Helmet. Includes SoftSeal® Ear Cushions, HushKit® Passive Noise Attenuation, and SoftSkin® Ear Seal Covers. This combo is designed to work with the plastic ear cups. (NSN 8475-01-591-3023) Find the right upgrades for your aviation helmet here Civilian Helmet Upgrades or Military Helmet Upgrades.