The product is made of cold-rolled steel plate, which is durable and corrosion-resistant. It makes up for the vacant grooves of the engine itself, the unsightly gaps between hidden tubes and various exposed frames and bolts. They also cover many grooves on the top of the engine. Grooves are notorious for collecting sand, gravel and other road debris while riding. The satin black finish makes these engine cylinder heads almost disappear, helping to keep the engine clean no matter where you ride. Install using existing bolts to ensure a firm installation