Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 77-90-0510 found under Valve Handle Nut by Allied Healthcare Products Inc. The National Stock Number assigned to this part is 4820012547617, 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 77-90-0510.