Wind vanes determine wind direction. Evaluation of the wind direction enables the best possible positioning of wind turbines. Ammonit wind vanes offer an excellent, fine resolution of 1°, while having very low energy consumption. It is essential that a wind vane covers an entire 360 degree radius, without a north gap. Cheaper wind vanes often have lower quality internal electro-mechanic fittings, which limit their life span, and a considerable north gap. Most wind vanes can be equipped with electronically regulated heating. Digital (TMR) and potentiometric wind vanes are available.