Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 012311.500 found under Stop And Stop Check Valve by W And O Supply Inc. The National Stock Number assigned to this part is 4810016422866, and the Federal Supply Class is 4810 Valves Powered. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 012311.500.