Replacing carbon brushes can fix an intermittent motor. Size:11mm/0.43" x 4mm/0.157" x 4mm/0.157" (L x W x H) Sold in set of 20 pieces Carbon Brushes with spring attached Worn brushes are often the cause of a poorly running motor ;New brushes can restore a motor's electric braking. Used widely for various of power tools and electric motors, such as rotary hammer drill, circular saw, cut-off saw and angle grinder. Carbon motor brushes are one of the most commonly replaced power tool components. Because carbon brushes are wear items, meaning that through friction and use they will gradually wear away, they will eventually require replacement. Worn brushes are common causes of intermittent motor function, reduced electric braking, and reduced motor power. Model Number : Electric carbon brush, Manufacturer: XXuan Store