Coarse Grit: 80 Grit
Extremely coarse; best for removing large amounts of material and rounding off corners
Medium Grit: 120 Grit / 180 Grit
Good for general purpose final sanding
Fine Grit: 240 Grit / 400 Grit
Used to roughen surfaces for painting or as a first passthrough for later sanding with ultra-fine grits