This is the bubble breaker or vacuum cap for your Ricoh Ri3000 Ri6000 and Anajet mPower MP10 and MP5 Garment Printer. This is what lays in the capping station gasket that stops the ink from bubbling up.
Installation: Smooth side up, channel side down. These just lay in there and float, they do not "clip" in.
Ricoh Part J0974148