Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 74-66 found under Ballast Lamp by Day Ray Products Inc. The National Stock Number assigned to this part is 6250008182321, 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 74-66.