Set up this free-standing heavy-duty umbrella base on your patio or at any outdoor event without worry. The free-standing umbrella base is crafted with a high-density polyethylene shell with UV protection that will not dent or fade, and can withstand the elements in any weather climate. This HDPE fillable base comes ready to be user filled with sand or gravel. Easily transport and set up the base with the removable wheel on the bottom and hand grips for easier mobility. The 24" diameter base features a 20" high stem that accommodates poles from 1 ½" through 2" thick. Inside the stem is a plastic post protector for the umbrella to rest on instead of a screw leaving the pole undamaged. The stem features two knobs made of polypropylene that tighten the umbrella securely in place for added stability and support. All of the steel components are made of grade 304 stainless steel. Grade 304 stainless steel is also used in aerospace engineering and surgical instruments.