"Edgeroll, Rubber, Gray [PN AD10/301C]. Use on HGU-22 series flight helmets like the HGU-26/P and HGU-2A/P. 3/4"" diameter with slit along entire length. Requires rubber contact cement to install on helmet. Works on Medium, Large, or XLarge helmets. Unissued in factory box. NSN: 8475-00-833-9485"