Drill bits come in various shapes and sizes. There are standardized size charts based on which the bits can be chosen.
Drill bits are made using different types of steel. Drill bits made with low carbon steels are softer and may require frequent sharpening or replacement. Drill bits can be made with high carbon steel, which is harder. High speed steels are also used to make drill bits.
Diamond coated drill bits can be used to drill holes in glass and other hard materials.