Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number M90-191 found under Adapter Waveguide by Microwave Engineering Corporation. The National Stock Number assigned to this part is 5985013882923, 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 M90-191.