Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number DA-40C NMP-1172 OPTION A found under Valve Safety Relief by Kunkle Industries Inc. The National Stock Number assigned to this part is 4820013316591, 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 DA-40C NMP-1172 OPTION A.