Vernier calipers have sliding jaws on a graduated beam. The sliding scale is used to measure between two opposite sides of a tool or part. The main fixed scale allows measurements in millimeters or inches while the sliding vernier scale provides a high-precision measurement. Compact slide calipers do not have a higher-precision second scale. They are small enough to fit in shop coat pockets. These calipers are commonly graduated with fractions of an inch and often used by woodworkers and for maintenance applications.