This set of three wire brushes contains three wire brushes. One made of some kind of polymer (nylon I think), one made of brown metal and the third one made of gray metal. Metallic gray is the hardest, followed by metallic brown and finally plastic. Three brushes, and no less. There is no fourth brush. If you are looking for two metal brushes and one plastic brush (three brushes total), then this product is for you. Each brush is slightly larger than a standard toothbrush. Do not use these brushes for oral hygiene.