You can't go wrong with 3M Roloc wheels. They will last as long as possible given the stress normally required to take on the end of an angle grinder. Make sure you have a 3" mandrel and make sure you want 36 grit as that is a gravel sized grit. Ideal for grinding welds or removing burrs that you can't reach with a larger electric grinder. 5 slices is a good margin if you use this sand sparingly. I usually burn one of these per project. Too bad I didn't buy a bigger box and more grit around 50-80.