Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ELF646 found under Tool Air Check Valve by Elf Machine Works Inc. The National Stock Number assigned to this part is 5120006467576, and the Federal Supply Class is 5120 Hand Tools Nonedged Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like ELF646.