Altimeter, Type MA-1
This is a Cold War / Vietnam War era Altimeter, Type MA-1, made by Aerosonic, part number A-80-MA, used in aircraft of the US Air Force such as fighters F-86 Sabrejet, F-100 Super Sabre, and F-104 Starfighter. MA-1's were also used in UH-1 Huey Helicopters. This example has a serial number prefix of AF-58, likely made for an Air Force order in 1958.
The knob in the lower left corner adjusts the altimeter for the barometric pressure, as indicated in the small window at the 3:00 position. This altimeter has a service label of SMAMA, Sacramento Air Materiel Area at McClellan AFB, California. SMAMA was responsible for servicing US Air Force aircraft F-100, F-104, F-105, F-84, F-86, T-28, A-1, T-6, and EC-121.
The indicator is in exceptional cosmetic condition, the glass and case are intact, the knob turns, albeit stiffly, and the lettering is clear and precise. Measures 3.25 inches diameter and ~5 inches deep.