Standard Crack Monitor has a simple design, is easy-to-use, and provides a measurement range of 20mm (0.78in) horizontally and 10mm (0.39in) vertically. The unit consists of an overlapping upper plate which is transparent, with a red crosshair indicator. The bottom plate is white with a measuring grid marked in millimeters. It offers 1mm (0.04) readability. This monitor has no fixture for use with calipers.