Dial gauges intended for measurement of lengths comparable with the range of a micrometer are generally multi-revolution types with a continuously graduated dial, with the numerals increasing increasing clockwise, Some also have numerals increasing anticlockwise, for measuring in the reverse direction. A purely reverse-reading dial is for use on depth or bore gauges. Those gauges intended for comparison measurement have a balanced dial with the numerals increasing in both directions from zero, for reading small differences from a reference surface, and may be limited to one revolution to aid error-free reading.