The Fowler Shockproof stainless steel dial caliper has dial graduations of 0.001" or 0.02mm with 0.001" and 0.02mm accuracy, shockproof anti-backlash control, a sliding jaw with a lock, and a covered rack. This caliper is used for measuring inside dimensions (ID), outside dimensions (OD), depth, and step. Shockproof spring anti-backlash control with a heavy-duty spring offers increased accuracy over standard gear configurations. Backlash is the amount of clearance between mated gear teeth in the caliper controls that prevents the gear teeth from jamming. It is undesirable to have much backlash due to the lack of precision offered by the increased amount of play between gears. Certain gear designs can minimize or eliminate backlash; spring anti-backlash systems use a spring to add a compressive force, thereby minimizing backlash. This caliper has a knurled lock screw to hold the sliding jaw in position and help ensure a consistent measurement. A covered rack prevents dirt and debris from clogging the gear, and helps prevent measurement errors. A thumb-operated fine adjustment roller allows for one-handed use. The caliper measures 0.10" or 2mm per revolution of the dial. The dial has 0.001" or 0.02mm graduations, and the beam has engraved 0.1" or 1mm graduations. The hardened stainless steel components, including the bar, measuring surfaces, rack, gears, and depth rod, offer corrosion resistance, increased accuracy, and long life. Self-contained movement eliminates gear misalignment, while the dual pinion drive mechanism reduces wear on the rack and pinion. An adjustable dial enables setting zero. The hardened stainless steel is polished to a satin chrome finish, to help prevent glare. This caliper comes with a fitted case. Dial calipers are measuring instruments commonly used for inspection in manufacturing to provide the precise measurements of an object. A pair of jaws attached to a long beam with a marked scale is used to measure inside, outside, and step measurements in standard or metric units. An additional depth probe slides along the beam to take depth measurements. One jaw is fixed to the end of the scale, while the other jaw slides along it to take measurements. A circular dial indicator is fixed to the movable jaw on a toothed gear rack that transfers movement of the jaws to the dial needle. The base measurement is taken from the long beam, which provides the initial whole measurement in inches or centimeters, and added to the dial reading, which provides fractional measurements in inches or millimeters. A locking mechanism provides the ability to take differential measurements for determining the difference in measurements between two objects. Compared to digital calipers, dial calipers are more durable, but are more susceptible to shock damage and prone to getting dirt in the gears, which can cause accuracy problems. Vernier calipers are more durable than dial calipers because they do not have internal moving parts, but they can be more difficult to read. Dial calipers are commonly used in fields such as metalworking, mechanical engineering, machining, and carpentry. The Fred V. Fowler Company manufactures inspection and measurement instruments such as electronic indicators, calipers, bore gages, and digital scales. The company, founded in 1946, is headquartered in Newton, MA. What's in the Box? Fowler Shockproof dial caliper Fitted case Dial graduations of 0.001 or 0.02mm, with one revolution equivalent to 0.100 or 2mm Hardened stainless steel construction for corrosion resistance and long life Shockproof antibacklash control with heavyduty spring for accuracy Knurled lock screw holds the sliding jaw in position to help ensure a consistent measurement Covered rack to prevent dirt and debris from clogging the gear, and to help prevent measurement errors