Tube Hole Gages utilize a precision three-point contact, self-centring system, for measuring both Tube and Tube sheet ID. Our Reversible Dial Plate, allows the user to measure in both inch/decimal and metric units. Our standard adjustable depth is 4” or 8”(101 or 203 mm) dependent on model. We offer additional 8” (203 mm) reach extensions to increase the capacity of these tools for Fin Fan and similar units. All gages are furnished with both setting ring and carrying case.