Deep Throat Dial Thickness Gage 0-0.4", 16" ReachDial Thickness Gage Deep Throat Thickness Gages are precision measuring tools used to measure the thickness of materials in hard to reach or confined areas. They are designed with an extended reach or "throat" that allows them to measure the thickness of materials in areas where traditional thickness gages cannot reach. This gage includes a 0 0. 4" measuring range with a 0 16" deep reach, allowing you to measure thickness in hard to reach places. The