Hardened stainless steel main scale and measuring jaws,knurled locking screw for more convenient measurement and reading. Glass fixed grid,stable,and high accuracy.Quick display of the measured value on LCD screen,no over-speed error. With on-off power button,automatic power off,waterproof IP54. Zero-setting at any position,mm/inch measurement system conversion. With data output function,Convenient and direct precision measurement for measure the depth,step,external and internal.