Used on w/s: submarine auxillary and miscellaneous systems; seawolf class ssn; trident auxillary systems. 2.230" inside diameter 0.067" major thickness external ring style item to be per mil-r-21248, ty 1, cl 2. can be purchased from truarc co. part number 5100-243 or equivalent. part is machined down to thickness .067 - .068 at general dynammics. cadmium surface treated
