Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 8606S499 found under Valve Hold Boom Hoist Cylinder by The Entwistle Company. The National Stock Number assigned to this part is 4820013186271, 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 8606S499.