Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number 635A21 found under Waveguide Assembly by Microlab Fxr. The National Stock Number assigned to this part is 5985005579725, and the Federal Supply Class is 5985 Antennas Waveguides And Related Equipment. Our website is owned and operated by ASAP Semiconductor, a leading distributor of aviation and aerospace part numbers like 635A21.