The rugged and electronic-free Vaavud wind meter turns your compatible smartphone into a high-tech meteorological tool, measuring wind speeds up to 48 knots with near-professional precision. Its unique design and electronic-free technology provide durability and reliability to meet the demands of an active life and the powerful Vaavud App provides an extremely easy to read and user-friendly interface, with the potential for expanded functionality and interaction.With its compact two cup design, inspired by professional anemometers, the Vaavud wind meter is accurate, practical and pocket friendly. It has a one piece durable plastic rotor and low friction PTFE bearing. Reliability and long service life are assured through the use of revolutionary electronic-free technology, communicating directly with the magnetic field sensor in your smartphone.The Vaavud App measures and displays wind speed in commonly used units of measurement. It has a neat and clean interface that shows actual, mean, and max wind speeds. The smoothed graph provides additional data on variations in strength as well as a quick overview. The graph supports zoom so data can be viewed in fine detail.The Vaavud wind meter has a wind range from 4 knots up to 48 knots (2m/s up to 25m/s). Accuracy is the lower of +- 4% and 0.4 knots (0.2m/s), with testing and calibration confirmed in the professional wind tunnel at the Technical University of Denmark. The cup anemometer design makes the Vaavud less sensitive to the way it is pointed; a weakness in impeller type wind meters.The Vaavud wind meter application works on iOS or Android smartphones. The electronic-free signal transfer utilises the magnetic field sensor (digital compass), in your phone or tablet. To be able to detect high wind speed this sensor requires a high update/refresh frequency.See www.ronstan.com for the most up-to-date information on Smartphone compatibility.