2pcs Carbon Brushes Repairing Part for Rotary Tool for Dremel 4000 Size: 6.3x4.8x8.4mm Quantity: 2pcs Application: Suitable for Dremel 4000. Step 1: Use the wrench to open the cover of carbon brush. Step 2: Take out the carbon brush. Step 3: Replace with the new carbon brush. Step 4: Use the wrench to lock the cover well. Package Included: 2 x Carbon Brushes