Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number V33-F4N-1-B found under Valve Check by Barbee Valve And Supply Inc. The National Stock Number assigned to this part is 4820016285131, 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 V33-F4N-1-B.