Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 0638A1 found under Boot Power Transmis by United Air Filter Company. The National Stock Number assigned to this part is 2520013476388, and the Federal Supply Class is 2520 Vehicular Power Transmission Components. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 0638A1.