Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number M8B-21A found under Shaft Shouldered by Wilden Pump And Engineering Co. The National Stock Number assigned to this part is 3040012406141, 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 M8B-21A.