Many times a tape measure just won't provide the accuracy you need when working on your car. Our OEM caliper measures objects up to 6 inches or 150mm in length. It is made from hardened stainless steel, has a large easy-to-read digital display and a switch to change from inches to mm. Additionally it has: two sets of jaws for reading inside diameter as well as outside diameter, a thumb wheel for easy tensioning, a locking thimble to hold the reading, and a hard-shell plastic case for storage. Will measure down to .0005 inch or .01mm. Comes with extra battery.