Notes: 2043098 STUD ACCIAIO CL. 10.9 UNI EN 20898 R18X2 is original CATERPILLAR product. 2043098 STUD ACCIAIO CL. 10.9 UNI EN 20898 R18X21 is commonly used in transmissions/axles/engines . if you have any questions please do not hesitate to contact us via Whatsapp +17275652849