Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 999-1231 found under Gasket by A L D Inc. The National Stock Number assigned to this part is 5330013743833, 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 999-1231.