Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number FVSP40 found under Seat Valve by Allen W D Mfg Co. The National Stock Number assigned to this part is 4820013405877, 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 FVSP40.