This caliper tool is made of high quality stainless steel, which is dustproof, waterproof, impact resistant, rustproof hence it has a long service life. The digital calipers can measure depth/step/internal/outer diameter with two sets of jaws ( upper and lower ) and a depth two measurement units can be converted for easy and accurate readings. Ideal for users who often work with overseas products.sliding digital unit section automatically starts the power without pressing the on/off button. 5 minutes without any operation, the caliper automatically turns off, which is more energy-saving and environmentally friendly. It also prevents the power from being turned on accidentally. The movement of sliding part is very light. Equipped with zeroing function for comparison and indirect measurement.