I gave this product 1 star but it saved me a few bucks in the end. The original roller brush on my Shark RV850 robot vacuum was worn out and needed to be replaced. With an old brush, the vacuum robot did not work for more than a few seconds. When I called Shark they asked $33 just to replace the roller brush. I found this and decided to give it a try. The roller brush fitted perfectly and gave me no problems. a while. The hair clipper came in handy too. But as for the vibrating brushes, that's absolute rubbish. 2 of them burst in less than 5 days. I only replaced one of the two rocker brushes when reviewing this order as the original Shark brush looked like it needed replacing. He lasted almost a year. So I replaced it with one of these and the replacement broke the same day - during the first run of the vacuum. I wasn't happy but since the roller brush worked I figured I'd let it go. So I installed a new one and let it run once. It also broke on first use. There were no obstacles or things to get stuck on. I only used furniture on the floor as carpeting. Having 2 breaks at once is just ridiculous. If you are looking for new rocking brushes, DO NOT buy them.