Notes: 129001-22900 PISTON ASSY, 0.25 OS is original YANMAR product. 129001-22900 PISTON ASSY, 0.25 OS5 is commonly used in transmissions/axles/engines 4TNE88-SA, 4TNE88-G1A1, 4TNE88-G1A01, 4TNE88-EG1A, 4TNE88-NS, . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849