Wind speed measurement accuracy: ± (3% rdg + 0.2 digit); Measurement method: vane type; Power supply: coin type lithium battery (CR2032) x 1 (sold separately); Width x Depth x Height: 5.7 x 1.0 x 1.9 inches (144 x 26 x 47 mm); For air conditioners, duct vents, civil engineering, construction sites. Includes wind speed and temperature display function. It has an average display function of 13 data.