Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 3535-3 found under Valve Check by Hpm Corp. The National Stock Number assigned to this part is 4820009398991, 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 3535-3.