Special Features:

Waterproof; available in normal galaxy colors and with the phosphorescent glow dial face; black only; shipping weight 1 lb

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.