This tool was designed for more precise measurements while trimming and throwing sets of pots.
1. Get an exact measurement of the bottom thickness before trimming, and while trimming, constantly checking how much clay can be removed from the base so that it won't go though or been left too thick.
2. A clever update of the classic Tombo sticks. By adding o-rings to the rulers, people can hold the tools in positions to get more accurate measurements when make sets of cups/bowls.
If you don't have a power bench grinder, you can use a fine diamond file or a sand paper filing or sanding the bevel until the blade has regained its edge. A video of the sharpening methods can be found below.