Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 181-5023AP found under Valve Vent by Acme Products And Engineering Inc. The National Stock Number assigned to this part is 4820011550320, 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 181-5023AP.