Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 5550 found under Shutter Radiator by Evans Tempcon Inc. The National Stock Number assigned to this part is 2930003509245, and the Federal Supply Class is 2930 Engine Cooling System Components Nonaircraft. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 5550.