I use three grits: 320, 400, 600. The 320 is used only rarely, so it sits off to the side. (Also, 320 is heavier, and very easy to distinguish by look or feel). So my only challenge is sorting the 3 vs the 4 hundred grits. I buy these on rolls, thus cut my own small strips for use. The 600 are cut with the ends square, overall shape is a long rectangle. The 400 are cut so the ends are at an angle, about 30~40 degrees. So in use, it is very easy to see if the piece has an angle cut or a square end. The "shape" does not wear off with use as marking does. I am quite happy with this solution. In fact, I am a 2% happier pen turner since I started doing it this way, and it all adds up!!:biggrin::biggrin: