This item is solar power . Put it in the office or the living room is very beautiful. It is made of high borosilicate glass, clear to see. When you put the in the sun the vanes will keep spinning. It is a creative gift, can send it to our friends or family. They will love it! Features - Color: Yellow. - Material: High borosilicate glass. - Size: About 13.00X8.00X8.00cm/ 5.11X3.14X3.14inch. - It is fascinating to hold it in the sun or to a light bulb and see vanes spin. - The stronger the light, the more energy there is causing the vanes to faster. - The purpose of this object is to measure the electromagnetic radiation strength. - Light pressure windmill is a very magical solar scientific experiment equipment. - The is a great home decoration or holiday gift. Of course, it can also be a physics teaching tool. Package list: 1 x