1. Made of high quality stainless steel material. 2. Professional precision manufacture for and precise adjustments. 3. Double sided (one side for smaller lenses, other side for larger). 4. It can remedy lens filter threads and dented lenses. 5. Increase small and large size of radius mutual complement, small radius semicircle align the position to be corrected when use, large radius semicircle align right place to reduce the pressure. 6. add a semicircle plus a straight line, you can observe whether it has been repaired during the repair station. 7. Double-side different radius circles combination, to suit different caliber lenses. 8. add 2 bearings so that they will be easy to use.