This small but very precise wind meter measures wind speed and direction. It is compatible with iPhone, iPad, iPod, and Android smatphones/tablets. iOS6.0 or Android 4.3 operating systems required. Just plug it into the audio socket. ± 0,5% or 0.1 m/s max error. 0.1 to 56 m/s range. It reads in meters/second, miles/hour, knots, kilometers/hour, & Beaufort scale. It saves wind speed (average and max) and direction. Shock-proof rubber case.