Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 204 66138 3 found under Orifice Cooling System by The Boeing Company. The National Stock Number assigned to this part is 1660013908373, and the Federal Supply Class is 1660 Aircraft Air Conditioning Heating And Pressurizing Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 204 66138 3.