Fiberglass-reinforced super polymid construction. Range of 0-6-inch/0-150mm. Direct .001-inch readings. Graduations .001-inch increments with 0.100-inch per single revolution of dial; 1.0mm bar scale. Dial adjustable to zero. Four-way measurements: outside, inside, depth and step. Comfortable friction thumb roller opens and closes caliper. Large, easy to read black numbers and markings on white background. Fitted clear plastic storage case.