Rancilio Copper Gasket - 3/8" Fittings A thin 21 x 17 x 1mm copper washer sized for 3/8" fittings, used throughout Rancilio commercial equipment, on overload valves, boiler fittings, the Silvia steam valve body, the Over Pressure Valve (OPV), and more. SPECIFICATIONS 21 x 17 x 1mm; copper COMPATIBILITY Fits: Rancilio commercial overload valves, boiler fittings, Silvia steam valve body, and OPV Replaces: Rancilio part #27350001 (also listed as R_3) INSTALLATION DIY, swap whenever you break one of these fittings loose. PRO TIPS Copper gaskets take a permanent compression set once torqued, if you're chasing a persistent weep at any 3/8" fitting on a Rancilio machine and didn't replace this gasket the last time that fitting was opened, that's very likely your leak.