The bristles of a worn main brush are prone to deformation and shedding, making it easy to entangle hair and pet fur; after replacement, the combing structure or anti-tangle design of the main brush can reduce hair jams. A worn main brush can create friction noise with the floor or roller compartment during rotation; replacing the main brush can reduce noise by 10-15 decibels. When the main brush is worn, resistance increases, which adds to the motor load; after replacement, the main brush runs smoothly, reducing motor wear and extending its lifespan. A deformed main brush may expose the internal roller bracket, which can scratch smooth surfaces like wooden floors and tiles; replacing the main brush effectively prevents this issue. 3PCS Main Roller Brush ,Compatible For Conga 2290，Robot Vacuum Cleaner Spare Parts