Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 121-B-04 found under Pipe Metallic by Imperial Inc. The National Stock Number assigned to this part is 4710014885098, and the Federal Supply Class is 4710 Pipe Tube And Rigid Tubing. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 121-B-04.