Keep precise records of barometric pressure readings with this exceptional, German-made barograph. Mechanical and with eight round diaphragms, it measures variations in the air pressure and transfers the information very precisely through a system of mechanical levers to a writing arm.It doesnt require winding as the battery-operated quartz movement rotates the solid brass drum once a week. And, as a result, it‘s more accurate than key-wound movements. The conventional ink nib and messy ink bottle are replace by a convenient felt tip pen, which lasts six to nine months. It includes a bottle of damping fluid for the arm to avoid incorrect readings when on ships or yachts at sea. The mahogany and glass case is polished to a high luster finish and is hinged for easy access to the movement for changing the paper and pen.Chart duration: 7 daysOne-year supply of weekly charts includedIncludes AA battery, felt tip pen, damping fluidCase dimensions: 11" x 6 3/4" x 6 1/2"Chart size: 3 5/8"Chart range: 28 1/2" to 31"