Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number S20A4B found under Shaft Shouldered by Pentair Pump Group Inc. The National Stock Number assigned to this part is 3040012122504, 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 S20A4B.