Dear manager, first of all I wish you success in your work. I have a request from you: I recently bought S7 Sonic. The machine is fine, but I found that its brush failed to pick up some litter and bristles. There are many other people having the same problem, you can be sure. I wonder if the bristle brush compatible with the S7 cannot be removed as a spare part alternative besides the rubber brushes we are using now? I believe that this will be an easy undertaking in terms of your technological infrastructure. Be sure, it can be seen that even a very simple residue cannot be removed due to the lack of this brush. Please consider this call. Thank you very much. I wish you good work.