The Model 4728 rear projection finish coat 1000 ml.Screen Goo Rear Projection coating SPRAYED (only) on a suitable substrate are all that's required to create an excellent Rear Projection screen. No Reflective Coat required.Suitable substrates include Glass, Plexiglas, Lexan/Polycarbonate in Clear (fully transparent) or slightly Tinted varieties up to 0.25 inch thick.