Started with replacing the roller brush. After a few seconds of work, the robot stopped and told me something was stuck underneath. I ended up putting the old brush back in. I started using the robot with an old brush and two new side brushes. The next day I grabbed the robot to move to another room (I have very weak internet) and found that there weren't enough brushes. The only thing left attached to the robot was part of the brush attachment. I found the brushes in another room. Don't waste money on this product. Find another brand, or even better, buy genuine parts. I go to show: you get what you pay for!