Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 13X-18 found under Oil Seal Special by Portersville Valve Company. The National Stock Number assigned to this part is 5330010937381, 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 13X-18.