Special Features:

Dimensions 3.100 inch length by 2.100 inch width by 1.100 inch depth; altitude pointer can be rotated to compensate for atmoshperic pressure fluctuations; self contained lighting system; velro wrist mount panel; batteries either silver oxide or lithium; used as a military parachuting altimeter for high altitude, low opening operations

Properties:

A barometric type instrument consisting of a pressure-sensitive element which contracts or expands in proportion to atmospheric pressure, connected through a linkage to a pointer. Its dial is graduated in units of linear measurement (feet, meters, etc.) and units of pressure measurement (pounds per square inch, inches of mercury, millibars, etc.) to indicate both atmospheric pressure and differences of elevation.