Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 81C-1-2 found under Valve Check by I T E Imperial Corp Subsidiary Of. The National Stock Number assigned to this part is 4820010813762, 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 81C-1-2.