21 x 17 x 1 mm thin copper washer for 3/8" fittings. Fits the commercial model overload valves and boiler fittings, the Rancilio Silvia steam valve body and Over Pressure Valve (OPV), as well as many other fittings in Rancilio equipment. Rancilio part number 27350001. Also listed elsewhere as R_3.
WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information, go to www.p65warnings.ca.gov.