Mach Airspeed Indicator flight instrument gauge. 

Make/Model LSI B0243-81925

It is untested. I do not know if it works or works properly. This was instrument came out of a Douglas DC-8 jetliner. These planes were pulled from commercial service in 1991.  I don't know if this is still in working condition. There's no visible damage or anything that would indicate that it doesn't work.