: Gauge Monitor is acrylic, so it is, sturdy, smooth, wear-resistant, and not easy to break : 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 Clear and Precise: Monitor is designed with a highly clear acrylic sheet and an easy-to-read measurement grid, so it is clear and precise It is very practical Design: Measurement Tool consists of two boards that overlap for part of their length The bottom plate is calibrated in millimeters, and the top plate is with a thin lines cursor in the shape of a cross Great Purpose: To tell the story of manual work Gauge is used to monitor cracks in wall and how they measured, Manufacturer: SHANGYAKEJI