Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5M9621 found under Stud Welding by Caterpillar Inc. The National Stock Number assigned to this part is 5307000041605, and the Federal Supply Class is 5307 Studs. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 5M9621.