This is a high quality teaching barometer, which is completely enclosed in a transparent plastic case, with movements clearly visible for the demonstration of its working.
The plastic case is sealed and provided with a flexible tube and a small squeeze bulb.
The barometer has a sensitive and accurate movement, with a 100mm circular dial, graduated 28 to 31 inch of mercury and 960 to 1060 millibars.
The scale is designed for maximum clarity and ease of reading.
It includes a resettable index pointer and a provision for wall mounting.
The actual effect of increasing or decreasing pressure can be observed, in the exposed aneroid, as air pressure is changed by squeezing and releasing the attached air pressure bulb, a small bleed hole being provided in the tubing near the bulb.