Referred to as the "GASKET FOR DOUBLE POD EPDM 90 Sh[ore]", 55 mm O.D. x 45/50 mm I.D. Pictured upside down. You will still need to keep both your original group head gasket installed as well as this one. The screen holder slips inside this, the screen goes onto the plate, and the screw goes through all, affixing the assembly to the group head.