Thank you for selecting Aerospace Aviation360 as your go-to distributor of part number SM-B-651390 found under Attenuator Variable by Microlab Fxr. The National Stock Number assigned to this part is 5985010324197, 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 SM-B-651390.