My 275 came from the factory seriously shaving sharp, with an uneven 30° back bevel by eye, but an even 30° apex according to a sharpie. Not knowing what grits came with a Sharpmaker, I happily sharpened away with the medium and fine stones and levy pants stropping, and while I could get it plenty sharp, I never matched the factory using the technique given in the instruction video. I then bought a pair of ultra fine Sharpmaker stones, which turned out to be so fine, as to have been reported as a good alternative to a 16,000 grit strop for straight razors! At that point the 275 was better, plenty sharp, so I used it. One of the boys took a shine to the Adamas and used it for much rougher stuff than I: rock hounding, bamboo, tree limb removal, etc

I now use 320 and 400 wet and dry sand paper held on the Sharpmaker stones with bull clips to iron out the edge b4 going to medium. (I should say that I told my son that the 275 could be used to make a fire pit if need be which was his rationale for digging up some cool stones)
Sal is reported as stating the following: "both our diamonds and CBN are 400 mesh, or ~40 micron." and
"mediums, 12-14 microns, 800-900 grit, fines, 7-9 microns, 2000-3000 grit, ultrafines, 3-4 microns, 4000-6000 grit."