Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 3987 found under Packing Preformed by Sperre Industri A S. The National Stock Number assigned to this part is 5330251500193, 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 3987.