Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number S4F203 found under Gasket by Optex Systems Inc. The National Stock Number assigned to this part is 5330001719010, 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 S4F203.