Set up this free-standing umbrella base on your patio or at any outdoor event without worry. The US Weight Umbrella Base is crafted with a high-density polyethylene shell with UV protection that will not rust, dent, or fade, and can withstand the elements in any weather climate. This stable base must be filled with sand or gravel. Easily transport and setup the base with the removable wheel on bottom and hand grips for easier mobility. The 20.5" diameter base features a 14" 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. If used with a patio table, 14" clearance is needed. 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 and will not rust.