This tool assists in making Shells in two sizes. One size is 22mm hole to hole and top to bottom and is about 8mm thick. The second is 19mm hole to hole and top to bottom, and is about 7.5mm thick. The press provides great definition and a sweet shape. I recommend the use of a razor tool, or similar item, to help define the ridges, as there is a small amount of webbing on the outer edge. The webbing is not significant, but your shell will look much more finished with a simple "tweak" at the end.