Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number NMP-421 PIECE 27 found under Retainer Packing by Keystone Intl Inc. The National Stock Number assigned to this part is 5330012861723, 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 NMP-421 PIECE 27.