Built to sustain the unpredictable abuse of the wind, Grosfillex umbrellas are heavy-duty with extra strength made to bend but not break. They come with replacable fiberglass or wooden ribs and an extra large vent to release the wind pressure. Made with colorfast, easy to maintain Recacril Marine Grade or Outdura Marine Grade solution died acrylic fabric, these umbrellas will make your pool or deck area a comfortable, shady place to relax for many years. Remember to always lower the canopy in windy conditions. Operators discretion is advised to prevent wind and consequential damage