Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number AD2-21 ITEM NO 8 found under Seal Plain Encased by Sterling Electric Inc. The National Stock Number assigned to this part is 5330014590436, 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 AD2-21 ITEM NO 8.