Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SS-42XS4 ITEM 4 found under Retainer Packing by Whitey Co. The National Stock Number assigned to this part is 5330013627236, 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 SS-42XS4 ITEM 4.