The Perfect Line Plastic Putty Black, made of unsaturated polyester resin, is easy to apply with a putty knife on clean, dry and stainless surfaces. The product is easy to process, consistent, adheres well to plastic, steel surfaces and galvanized sheet steel, has an excellent finish and is also easy to sand. This black putty has a built-in control layer: places that remain black after sanding are not sufficiently filled.