The quality of the product is excellent and the surface of the wavy bristles picks up material really well. I think 4" is too big and heavy for a 41/2" grinder. Due to the high speed and imbalance of the wire wheel, the vibration of the grinder made it difficult to use over a longer period of time. I used it to remove primer and paint from a project car and it worked better with the primer than any other method I've tried, including a bristle cup brush. However, the speed of rotation combinedβ¦