Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number X2072 found under Valve Check by Derbyshire Mack And Morgan Inc. The National Stock Number assigned to this part is 4820011909566, 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 X2072.