Notes: 21173 SHIM RING DIN 988 90X100X0.5 C75 HV390-5 is original CARRARO product. 21173 SHIM RING DIN 988 90X100X0.5 C75 HV390-51 is commonly used in transmissions/axles/engines . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849