The classic barograph measures 7 3/4" x 5" x 5 1/4" and weighs 3 lbs. The chart size is 2 1/4". The chart range is 28.5 to 31". Record barometric pressure with this mechanical German-made Classic Barograph that measures variation in the air pressure and transfers the data through a system of mechanical levers to the writing arm. Housed in a rich mahogany case with glass sides and a polished brass handle, this barograph is equipped with a battery operated quartz movement with 4 diaphragms that rotates the solid brass drum once a week, requires no winding and is more accurate than key wound movements. The barograph readings are marked on paper inch charts with a felt tip pen. The chart duration is 7 days. It comes with a one-year supply of weekly inch charts. AA battery included. One felt tip pen included.