2. FIRM AND NON SLIP: The innovative rotating knob of the position marking protractor allows for quick adjustment of angle and position, and then firmly locks in place to prevent sliding during use. 3. HIGH VISIBILITY : The multi angle depth measuring ruler has crystal clear horizontal bubbles and an super accurate calibration function, enabling immediate horizontal inspection. Whether you are hanging shelves or aligning workpieces, the highly transparent design ensures easy reading 1. MULTI ANGLE MARKING: This Extendable depth measuring ruler supports accurate marking , making it highly suitable for woodworking, handcraft projects and professional workshops. The angle can be easily adjusted with the rotatable knob, ensuring position every time 4. FIXED POINT MARKING: Foldable depth measuring ruler is designed with dedicated marking capabilities to create accurate reference points on wood, drywall, and other materials. The non slip limit keeps the ruler stable during operating to achieve errorless measurement 5. LONG LASTING AND PORTABLE: This compact depth ruler is made of sturdy aluminum alloy and is foldable, making it easy to store in a toolbox or pocket, which is highly suitable for contractors, carpenters and amateurs who require trusted work, Manufacturer: Jnchdghwa