Airspeed / Machspeed Indicator Kollsman A3422310002
Here is a combination Airspeed Machspeed Indicator, 0-400 Knots, made by Kollsman. The mach number is adjusted for the aircraft with a hex key turning the blue screw on the rear case. Likely from the 1960s or 70s and a US Navy aircraft. Measures 3.25 inches diameter and 4.25 inches deep.