The main part of the base is made of heavy duty plastic. The bottom has compartments which you fill with sand in order to weight it down so the umbrella will not tip over. it's a very heavy, solid umbrella. After the sand is in, there is a heavy duty plastic cover you put over the top of the sand-filled unit. You then put the pole, which is heavy duty metal, into a hole in the center of the base and secure it with a collar mechanism. We have only had ours about a month, but there is no easy way to move this umbrella, so no, you would not want to take it in during the winter. It weighs about 300 pounds.
4 years, 7 months ago