Notes: 66000.1 STUD - - R22x2.5 - D22x1.5 - L88 - 10.9 is original DOOSAN product. 66000.1 STUD - - R22x2.5 - D22x1.5 - L88 - 10.91 is commonly used in transmissions/axles/engines . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849