Gauge Monitor is constructed from premium-grade acrylic, providing excellent longevity, structural integrity, smoothness, and resistance to wear Monitor features a highly clear acrylic base paired with easy-to-follow measurement lines, making analysis accurate and effortless Because our Gauge can monitor cracks in wall and how they measured, it is very practical and for you Our Measurement Tool features a millimeter-calibrated base and a clear top plate, incorporating a perpendicular reference line for alignment You can use our Corner Monitor to monitor the horizontal or vertical movement of cracks on a plane It is a carefully designed instrument, Manufacturer: RGYBAO