Notes: 20E-23K-1591 COMBI RING 42X62X21.5 SF6 is original KOMATSU product. 20E-23K-1591 COMBI RING 42X62X21.5 SF61 is commonly used in transmissions/axles/engines . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849