Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 28D1221REVB found under Insert Screw Thread by Allen Tool Phoenix Inc. The National Stock Number assigned to this part is 5325000731402, and the Federal Supply Class is 5325 Fastening Devices. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 28D1221REVB.