1. Accuracy measurements: accuracy for precision measurements. Accuracy up to 0.01mm, measuring range from 50mm to 160mm. One end of the measuring head is a movable probe and the other end is a replaceable probe that varies depending on the aperture measured. 2. Main function: Suitable for measuring workpiece diameter. Professional cylinder drill gauge, ideal for hobby machine builders and mechanics. It is widely used for measuring many types of automotive parts or cylinders and for easy testing for ovality or outofroundness. 3. quality material: This inner diameter gauge is made of quality stainless steel and plastic, manufactured to a standard for long service life. Dial drill gauge with carbidetipped contact points for extended wear and improved abrasion resistance. 4. PackagingPackage list: 1 x dial gauge; 12 x probes; 2 accessory kits; 1 x accessories and ABS storage case.