Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number B520-3001-3 found under Ballast Lamp by Essex Electro Engineers Inc. The National Stock Number assigned to this part is 6250012428374, and the Federal Supply Class is 6250 Ballasts Lampholders And Starters. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like B520-3001-3.