I have purchased replacement sets of 9 replacement parts for iRobot and all the parts look very good quality and fit together well. But I have problems with the universal rubber brushes. When I installed a set of rubber brushes, the vacuum became very loud and noisy when working. It makes a rattling or vibrating noise, especially when moving on a hard wooden floor. I've been using rubber brushes in my vacuum for a few weeks now and it's getting better (less noisy) but still noisy. When I put the original iRobot rubber brushes back in place everything is fine again. I thoroughly vacuumed all my hair etc. I didn't notice this aftermarket kit left any marks or anything on the floor or walls. The main complaint is the odd noise made by the rubber brushes. If you leave the vacuum running while you're away, you might not care. I think I can see that the vacuum won't move or climb over the edge of the carpet like the original brushes, but I'm not entirely sure.