The grinder works perfectly. I just haven't figured out how to keep the grinder wet. My machine's sponge doesn't get close to the sander, so I have to use a spray bottle, which makes sanding and spraying very cumbersome.
Bits are what I expected. I gave a lower rating because the packaging was opened and resealed earlier. Two hex keys were missing to tighten the bits on the shaft. This was fine with me because I have a collection of wrenches (there are 5 grinders for my art students) but if I didn't have wrenches it would be agony.