Feature●Accurate Measurements: Has an accuracy of ±0.001"/.02mm; raised sliding surface prevents wear and defacement of graduations, and a covered rack helps prevent dirt and debris from entering the gearing and helps prevent measurement errors●4 Measuring Capabilities: This dial caliper can be used to measure inside dimensions (ID), outside dimensions (OD), depth, and step measurements●Knurled Lock: Dial caliper features a knurled lock screw that holds the sliding jaw in position to hold measurement when needed; a thumb-operated fine adjustment roller allows for one-handed use●Colored Graduations: The large white dial has 0.001" graduations in black and 0.02mm graduations in red; one revolution equivalent to 0.10"/2mm●Set Includes: Fowler Dual Reading dial caliper, instructions, fitted caseDescription Fowler 52-030-006-1 Dual Reading Dial Caliper has a covered rack that helps prevent dirt and debris from entering the gearing and measurement errors. This caliper is used for measuring inside dimensions (ID), outside dimensions (OD), depths, and steps. The caliper is made of hardened stainless steel for corrosion resistance and long life. It features a shockproof design that prevents dial backlash, and knurled lock screw holds the sliding jaw in a position when required. Fowler, an American company, manufactures premium inspection and measurement instruments like electronic indicators, calipers, bore gages, and micrometers. The company, founded in 1946, is headquartered in Newton, MA.