The Tenmars TM-740. This is a mini, pocket size vane air flow meter (anemometer) with a digital display and a 30mm vane housed at the top of the unit. The Tennmars TM-740 can measure air velocity from 0.4m/s up to 25m/s with a resolution of 0.1m/s, and is also capable of measuring temperature from -20 up to +50 degrees Celsius. A dual display is capable of displaying air flow and temperature.