SavePlus Tschorn 3D Tester Probe - Ceramic Tip - 12mm Shank - 132.5mm Length (EX Shank) - 35mm Dial FaceBecause its diameter is bigger than the body of the 3D Tester this probe tip allows probing in almost endless depth and opens up new possibilities. When using slim tool holders to clamp the 3D Tester (diameter smaller than 50 mm), you can extend the depth of probing as deep as you want. Find your workpiece position and check parallelism in almost endless depth.