The environmental meter determines the wind speed via an impeller with a diameter of 65 mm. The environmental meter can reliably determine the speed in a measuring range of 0.3 … 45.0 m/s. - Measuring range: 0.3 … 45.0 m/s / 0.9 … 147 ft/s - Velocity and volume flow measurement - Telescopic probe with a length of 270 … 540 mm / 10.63 21.26 - Impeller opening of 65 mm / 2.5" - Interface: Micro USB - Data memory: 960 measured values