Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 1593 found under Valve Check by M D Holdings Llc. The National Stock Number assigned to this part is 4820011980622, 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 1593.