Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B501409 found under Valve Hand Outlet by Rollsroyce Airlines. The National Stock Number assigned to this part is 4820997758022, 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 B501409.