Notes: 1597400 STUD R22x2.5 - D3/4-16 - L86.5 - 10.9 is original CATERPILLAR product. 1597400 STUD R22x2.5 - D3/4-16 - L86.5 - 10.91 is commonly used in transmissions/axles/engines . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849