Specifications: Airflow 80-4900 ft/min, 0.4-30 m/sec Temperature -10-+50° C, +14-122° F with max./min Average memory with Data hold function, Temperature Sensor Battery Type and Life: 9 Volt/100 hours (under normal usage) Display Type and Size: LCD 37 mm x 42 mm (11/4” x 15/8”) Max Reading: 9999 Diameter of Fan: 70 mm (27/8”) with Auto Power Off 20 minutes Selectable Knot, Mile/H,