Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 16D AND PL-4533 found under Valve Check by Admiral Valve Llc. The National Stock Number assigned to this part is 4820012211575, 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 16D AND PL-4533.