Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number E420ALT6 found under Valve Regulating Fluid Pressure by Kieley And Mueller Inc. The National Stock Number assigned to this part is 4820001818911, 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 E420ALT6.