SOLAREZ repair putty is a mixture of clear, non-yellowing, high strength, fiber reinforced polyester resin and an amazing solar activated catalyst. There is no mixing required, just use it right from the tube. It gels in 30 seconds, curing in 3 minutes - but ONLY when exposed to sunlight. Proprietary forumula assures that millions of fiberglass fibers are throughly wet-out and evenly dispersed in every dose. Bubble-free mixture Denser cross-linking and surface cure No residual peroxides UV Stable Comes with 60/240 grit sand pad.