This barometer houses a highly reliable and accurate double diaphragm German aneroid movement that is visible through the open dial. It displays both of the barometric scales; inches of mercury and millibars. The movement is temperature compensated and calibrated for altitudes up to 3500 feet above sea level. Dial: 5-1/4". Base: 7". Depth: 3-1/2". Wt. 7 lbs 2.5 oz..