Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 2221A3-28B found under Lamp Cartridge by Jetronic Industries Inc. The National Stock Number assigned to this part is 6240001466678, and the Federal Supply Class is 6240 Electric Lamps. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 2221A3-28B.