Bondo Glass Reinforced Filler makes an excellent foundation for hole, dent and rust-out repairs without the need for backing strips, cloths and resins. It contains short, interlocking fiberglass strands and fibers that make it twice as strong as regular body filler. It is also slightly thicker and provides a fast drying time, making the filler less messy on vertical surfaces such as car doors. Can be paired with body filler and glaze for complete repairs. Sandable in as little as 20 minutes for quick repairs. Compatible with most paints. Waterproof formula works for cars and boats. Includes Bondo Blue Cream Hardener.