Solarez "Polyester" Fiberfill is UV activated for quick easy repairs on-the-go. Doesn't harden till placed in the sun so it allows you plenty of time to evenly disperse the mix. Solarez Polyester repair putty is a mixture of clear, high strength, fiber reinforced epoxy resin and an amazing solar activated catalyst. There is no mixing required, just use it right from the tube. It gels in 5 seconds, curing 3 minutes but only when exposed to the light. Great for the Nose, Rail, Fin or Tail.