Why are the foam abrasives called Medium, Fine, etc., rather than by their grit like normal paper?

When you put abrasive grain on a piece of foam, and then that foam hits a surface, some of the grain will push back up into the foam itself causing the grain to be less aggressive. For example, our FINE pad has a 100 grit abrasive grain on it, though it will give you a scratch more like a 220 grit-240 grit paper would. Check out our grit conversion chart: