Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number CB50-4 found under Seal Plain Encased by John Crane Inc. The National Stock Number assigned to this part is 5330008099125, 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 CB50-4.