Notes: 27231-550000 PLUG 55 is original YANMAR product. 27231-550000 PLUG 555 is commonly used in transmissions/axles/engines 4TNE98-SA, 4TNE98-G1A, 4TNE94-SA, 4TNE94-G1A, 4TNE98-ACG, . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849