Rancilio Sight Glass Upper Fitting Copper Washer
15 x 10 x 1mm. This part is used in old Rancilio models that DO NOT have the auto-fill probe inserted into the sight glass. It seals the upper sight glass cap fitting on old S-20 series (that have a sight glass), Z-9, Z-11 and Millennium model Rancilio's. Also found on the Classe 9 side boiler cap.