These very deep gouges are designed with a parabolic curve. They are designed to be rolled up to 90 degrees and change shape from deep #11 to a smooth #3 in one continuous cut. The thumbnail grind keeps the corners from digging into the wood as the tool is rolled. The FR920 set includes FR725, FR925, FR926, FR927. Sets of tools are more economical over buying tools individually. Choose from a number of sets based on the size of work you are doing and your pocket book. You can click on any set to view the profiles it contains.