Altimeter, 20,000 ft, Pioneer 2101-2A-B3-1287
This is a fine example of a WWII-era Altimeter, similar in specs to the B-12 only with a center knob instead of left corner, made by the Pioneer Division of Bendix. It is a standard, or non-sensitive, altimeter in that it has one pointer (sensitive altimeters have 2-3 pointers). This altimeter measures to 20,000 ft of altitude, with the pointer rotating once from 0-20,000 ft. It does not have a barometric scale, but the center knob is provided with which to rotate the dial, so that the pointer may be set to zero at any existing atmospheric pressure between 28 and 30 inches of mercury.
It is in good condition given its age. The knob, while stiff, still rotates the dial. The glass and case are intact. The glass is slightly dirty from the inside, but can be opened and cleaned if desired. The face has some pitting that gives away its age. The original seal is in place, located over the outer screw head at about the 13,500 ft mark on the scale. We were going to open and clean the glass, but elected not to disturb this original seal. Measures 3.25 inches diameter and ~3 inches deep.