Purchased with matching set of 3" nylon cone brushes to prepare a 5' x 8' painted and powdered trailer before applying 3 coats of primer. Coarse and medium brushes were used which lightly prepared painted surfaces and were strong enough to last long enough to make a 5'x8' powder coated bed. Also great for removing rust from metal surfaces. Note: If careless, they will strip painted surfaces down to the bare metal. (For reference Preparation of the coating only requires etching of the painted surfaces to be coated.)