Solarez Epoxy Resin repair putty is a mixture of clear, high strength, fiber reinforced epoxy resin and an amazing solar activated cataylst. There is no mixing required, just use it right from the tube. It gels in 5 seconds, curing in 3 minutes – but ONLY when exposed to sunlight. No mixing necessary; UV curing assures complete hardening. Provides complete crosslinking Remarkably tough and resilient Contains urethanes that keep from yellowing Eco-freindly ZERO vapors; non-flammable Comes with 60/240 grit sand pad in a crush-proof watertight capsule