Ceramic pottery measuring tools with straight legs for carving, shaping, clay sculpting and modeling. HIGH QUALITY: All calipers are made of stainless steel with solid points and finely polished, sturdy and durable to serve you for a long time. Grease with anti-rust oil to prevent rust. The internal caliper measures the diameters of the holes and the distances between the surfaces. PRODUCT FEATURE: Our caliper is a lightweight, easy-to-handle caliper that transfers measurements from model to clay for interior and exterior dimensions. The sturdy screw uses friction in the joint to keep the legs from moving. Practical Caliper: Great for you to measure the external and internal size that ordinary calipers can't reach, such as carving, pottery, tube, etc. Please note that it will be a little difficult to open it for the first time use, and the oil on the caliper will be lubricated once opened.