Features: 1. 100% brand new and high quality. 2. Light weight, stable performance and accurate measurement. 3. This product can connect smart device and display its reading. 4. Ergonomic design and it is easy to operate. 5. Mainly measure the speed and direction of average flow Specification: Condition: 100% Brand New Model: GM8904 Parameters: operating current unit minimum typical maximum mA 7 8 10 operating voltage unit minimum typical maximum V 3.6 5 9.5 Error: wind speed measuring error unit range resolution Threshold precision m/s 0 ~ 4 5 0 .1 0 . 8 ± 3% ± 0. 1 digits ft / min 0 ~ 8 8 0 0 19 157 ± 3% ± 1 0 digits knots 0 ~ 8 8 0 . 2 1.6 ± 3% ± 0. 1 digits km/hr 0 ~ 1 4 0 0.3 2.9 ± 3% ± 0. 1 digits mph 0 ~ 1 0 0 0.7 1.8 ± 3% ± 0. 1 digits Wind temperature measuring error unit range resolution precision ℃ -1 0℃-50℃ 0.2 ± 0.2℃ °F 14°F- 122°F 0.36 ± 3.6°F Communication port: port definition red DC power supply (3.6-5V) green RXD white TXD black GND Operating temperature 0℃-50℃(32°F-122°F) Storage temperature -20℃-60℃(-4°F-140°F) Weight: Approx. 134g / 4.7oz Size: Approx. 66 * 29.5 * 178mm / 2.6 * 1.2 * 7.0in Package List: 1 * Digital Anemometer 1 * CD 1、100% brand new and high quality. 2、Light weight, stable performance and accurate measurement. 3、This product can connect smart device and display its reading. 4、Ergonomic design and it is easy to operate. 5、Mainly measure the speed and direction of average flow