The bottom plate of our measuring tools is calibrated in millimeters. It also has a clear top plate and is marked with a narrow cursor Our monitoring gauge can monitor wall cracks and their progress, making it very practical and convenient for you Our corner monitors allow you to monitor the horizontal or vertical movement of cracks on a plane. This is a precision instrument The monitor uses high-transparency ABS sheet and easy-to-read measurement grid, so it is clear and accurate. Very practical The gauge monitor is made of ABS, so it is wear-resistant, smooth, wear-resistant and not easy to break, Manufacturer: Rxgiasup