Notes: 129907-22090 PISTON ASSY, 18.5 is original YANMAR product. 129907-22090 PISTON ASSY, 18.55 is commonly used in transmissions/axles/engines 4TNV98-YTBL, 4TNV98-YTBL2, 4TNV98-VTBZ2, 4TNV98-VTBZ, 4TNE94L-1B46C, . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849