Specification: Measurement in SAE (inch), with a measuring range of 0-6", an accuracy of 0.001", and a resolution of 0.001". This is the perfect dial caliper for machining, household use, DIY projects, or any other precise measurement needs 4-Way Measurements: Equipped with dual jaws and a probe, this caliper measuring tool allows for 4-way measurements, including inside, outside, depth and step measurements, providing comprehensive utility User-friendly Design: The precision caliper features a knurled thumb roller to ensure smooth sliding, a locking screw for accurate positioning, and a measuring dial that is scratch-resistant, anti-glare, and easy to read Durable Construction: The SAE caliper is made of finely polished stainless steel and uses double shock-proof technology for increased durability and high precision. The padded case allows the analog caliper to be safely stored when not in use, making it more convenient and easy to carry "When the Dial Hand is Not at Zero: 1.Make sure there is no dust on the faces for external measurement. 2.Close the jaws, loosen the dial locking screw and rotate the dial bezel"