Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number ASTM B438 B438M found under Bearing Washer Thrust by American Society For Testing And. The National Stock Number assigned to this part is 3120002878054, and the Federal Supply Class is 3120 Bearings Plain Unmounted. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like ASTM B438 B438M.