A vernier scale is a visual aid to take an accurate measurement reading between two graduation markings on a linear scale by using mechanical interpolation; thereby increasing resolution and reducing measurement uncertainty by using Vernier acuity to reduce human estimation error

The caliper has a dual vernier scale, with both the upper and lower scales measuring in metric units. A 14-degree vernier face angle improves visibility and helps prevent parallax error in measurement reading. The caliper’s two sets of jaws provide the capability to make OD and ID measurements, as well as step measurements, where the butt end of the fixed jaw measures one end of a work piece before its upper/lower or inner/outer steps are measured. When included, a depth-measuring blade with rounded edges provides the ability to make depth measurements. The scales are raised to slide easily and protect the graduation markings. A thumbwheel permits fast and easy measuring. A clamping screw on the upper scale rotates to control scale movement and locks to hold the sliding jaw’s position. The caliper is made of hardened, corrosion-resistant stainless steel with a satin chrome finish that helps reduce glare