Gauge Monitor is acrylic , so it is , sturdy, smooth, wear-resistant, and not easy to break. Clear and Precise: Monitor is designed with a highly clear acrylic sheet and an easy-to-read measurement , so it is clear and precise. It is very practical. : Corner Monitor is a simple and cool analog-crack device and a precisions instrument used to monitor the horizontal or vertical movement of cracks on a plane. Great Purpose: To tell the story of manual work. Gauge is used to monitor cracks in wall and how they measured. Design: Measurement Tool consists of two boards that for part of their length. The bottom plate is calibrated in millimeters, and the top plate is with a thin lines in the shape of a .