Install solar batter plate on cap top or front to convert light energy into electric energy, driving the micro-fan on the peak to produce cool wind. The air quantity may be adjusted on its own with the change of the sunlight. The stronger the sunlight is, the air quantity becomes heavier, and one will feel cooler. When there is no sunlight, dry cells may be used to drive the fan. Solar panels: 30 * 30mm, 63mm diameter fan, common specifications 610/ 590/ 570/ 550mm hat PE