Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number U21751 found under Shaft Straight by Siemens Water Technologies Corp. The National Stock Number assigned to this part is 3040012597275, and the Federal Supply Class is 3040 Miscellaneous Power Transmission Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like U21751.