Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SM-B-447575 found under Clamp Hub by Spencer Industries Inc. The National Stock Number assigned to this part is 3040009731505, 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 SM-B-447575.