Within a minute of starting a cleaning cycle with one of these brushes installed, my Deebot N79S stops working, gives a loud alarm and reports the error "Main brush failure". the app. Have uninstalled and reinstalled it several times, the result is always the same. The vacuum ran every night for about 8 months and I have never seen any error messages other than getting stuck somewhere before trying these brushes. I will be returning them and recommend if you have an N79S not to order them.