Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 840 1 2IN SW found under Valve Check by Anvil Industries Inc. The National Stock Number assigned to this part is 4820011916384, 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 840 1 2IN SW.