This is a quality stainless steel 6" digital caliper with extra large digital display plus molded case. It will measure .001" to 6" or .01mm to 150mm. Also calibrates to zero, converts SAE & METRIC with a touch of a button, it has a locking screw, measures inside&outside, thumb roller, step measuring surface and a knife shaped measuring surface. The high quality caliper can be used every day by professionals.