Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number P5921 found under Seal Plain Encased by Pioneer Motor Bearing Co. The National Stock Number assigned to this part is 5330003915921, and the Federal Supply Class is 5330 Packing And Gasket Materials. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like P5921.