Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 9W-3939 found under Ring by Caterpillar Inc. The National Stock Number assigned to this part is 5330014682840, 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 9W-3939.