Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1J521-3-J1 found under Valve Diaphragm Stop by Rockwell International Corp. The National Stock Number assigned to this part is 4820011915896, and the Federal Supply Class is 4820 Valves Nonpowered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 1J521-3-J1.