Accurate cutting is required for stained glass production. The center of rotation does not know the exact position on the sucker. I need something like a needle whose center is clearly understood. In addition, glass for stained glass has irregular surface, may not be fixed with suction cup. In addition, I think that it is user-friendly as the arm is a little longer because its range of use is wide. The shape of the cutter is nice. It is the shape of the cutter used in Europe or the United States long ago, it is exactly a craftsman's favorite.