478 820 731 · O-ring Porsche genuine (OEM) part number 478 820 731, O-ring. Fitted on (3)SEAL. RING — pos 17 (KAT1001.BIN)SEAL. RING — pos 17 (KAT1004.BIN)SEAL. RING — pos 24A (KAT1005.BIN) Open the interactive exploded diagram →