Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number GV500LU4SAK found under Valve Check by Sargent Welch Scientific Co. The National Stock Number assigned to this part is 4820010048034, 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 GV500LU4SAK.