Description: 【Innovative Design】: The L shaped crack monitor is composed of two overlapping plates. The bottom plate is calibrated in millimeters, while the top plate is transparent and marked with a crosshair cursor for measurements. 【Accurate Measurements】: The ruler on the XY axis has a range of ±1 mm (±0.04 in) with a resolution of ±0.5 mm (±0.02 in). It offers a horizontal range of ±20 mm (±0.79 inches) and a vertical range of ±10 mm (±0.38 inches), providing accurate readings. 【Easy to Use】: You can easily secure the two plates together and then to the wall with screws and expansion screws, enhancing convenience and stability during use. 【Material】: Made from premium acrylic materials, this crack monitor record tool boasts durability and stability. easy to read, offering clear monitor results. 【Nice Accessories】: This practical and accurate measuring tool is used to monitor wall cracks and their changes over time, an essential tool for construction works. Specification: Material: Acrylic Color: White Size Chart: 10cmx8cm/3.94inchx3.15inch Package Size 15cmx15cmx3cm/5.91inchx5.91inchx1.18inch Package Includes: 1 Crack Monitor Record Tool Kit Note: Please allow slightly errors due to manual measurement and different monitors.