I've been using DMT products since the 80's. These 8" dia-sharps are my mainstay. After burglary, they're fairly graded and simply don't require maintenance of other stones. If you have a range (after medium-extra-fine, I have everything), you can use 4000 (6 microns) There has been a hole in this line for some time, nice to see it has been filled. sharp meaning the gradation is lower (coarser) than advertised. The stones wear down with use and I actually break them before I use them forβ¦