DURABLE Coastal™ shutters are constructed of Mikron Rigid Vinyl Extrusion RP-5534, an exterior-grade engineered PVC resin. This makes them superior to other shutters in many ways. They're stronger. RP-5534 is a 100% virgin resin compound engineered with special impact modifiers for strength. Coastal shutters have a macro-cellular construction. Internal "girders" reinforce the shutter, giving it incredible strength without unnecessary weight, very much like an aircraft wing. Coastal shutters have the highest strength-to-weight ratio of any shutter. They are 20-25% harder than wood or polyfoam shutters, and are less brittle than composites. Because they are harder, they resist scratches and impact damage better. They're lower maintenance. They can be cleaned with a damp sponge, and they're lift-off hinges allow for easy removal of the shutter panels. They will not warp, peel, chip or swell due to humidity. The color of a Coastal shutter is through-and-through, so no paint touch-ups or repainting is ever necessary Since this shutter's debut in 1990, more than 99% are still in place, looking and working as good as the day they were installed. They're safer. Coastal shutters are self-extinguishing, fire resistant and carry a flame spread rating of A (I), making them safe for public buildings, schools, elder and day care centers, and of course, your home. Coastal shutters are constructed from 100% non-toxic materials, perfectly safe for children and pets.