Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5540-1 found under Body Valve by 3D Instruments Llc. The National Stock Number assigned to this part is 4820015428392, 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 5540-1.