Angle-measuring devices come in several types. The most popular and widely known is a disk protractor - a half-disk made of glass/plastic. The see-through material makes it easier to see and measure angles in small geometric objects and drawings. The border of such protractor is covered with angle markers with degrees from 0 to 180. A bevel protractor is a more complicated variation of such device, it has a moving arm connected to a fixed arm with a dial, and can be applied to mark or estimate angles in construction, design, technical drawing, and similar appliances.