A depth gauge (AKA digital depth gauge or dial depth gauge) is a type of measuring tool that plumbs the depth of holes and recesses from surface. It consists of a narrow ruler, a base and a locking screw. The ruler is inserted into the hole, the base is slid down to the surface and the locking screw is turned to lock the base in place on the ruler at the surface level where the depth measurement is indicated. Products vary by range, resolution, inclusions and other considerations. For more measurement tools, especially distance measuring, check out our distance meters and our measuring wheels.