Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number G520 found under Valve Non Return by Imi Norgren Ltd. The National Stock Number assigned to this part is 4820004769611, 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 G520.