You can use it on a variety of substrates like steel, aluminum, fiberglass and many more Ideal for minor body work and surface imperfections like sand scratches, chips, pinholes and more Top Coat: Polyester, 2K urethane or 1 K primer (773) 386-4806 (773) 225-5979 https://www.5startools.com/tools-1/kar007-polyester-auto-body-glazing-finishing- pourable-putty-24-oz