Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number FSS4R2122 found under Reducer Pipe by Mutual Mfg And Supply Co. The National Stock Number assigned to this part is 4730013548996, and the Federal Supply Class is 4730 Hose Pipe Tube Lubrication And Railing Fittings. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like FSS4R2122.