Diamond-coated files cut faster and leave a smoother finish than ordinary steel files. The diamond files from Hobby Tool Supply work on wood, plastic, ceramics, metal, glass and just about anything else. And, because the abrasive is made of genuine industrial diamonds brazed to nickel-plated steel handles, they last far longer than ordinary steel files. All files are diamond-coated on all sides. The handles are coated in red PVC for improved grip.