LOOYUAN 6-Pack Replacement for iRobot Roomba 800 Series 880 870 3-Armed Side Brushes + Cleaning Tool Compatible with iRobot Roomba 800 Series 6 pack Side Brushes +Cleaning Tool for Roomba 800 Series 3 Armed 880 870 Replacement iRobot Roomba 880 3-Arm Side Brush Replace side brush every 2 to 3 months for best performance The Brush allows your Roomba to reach deeper into the carpet for a more thorough cleaning