This 9 Ft. octagonal aluminum market umbrella has a 1.5” diameter center pole and 1/8” square aluminum ribs. The parts are made of stainless steel and the frame is silver mist coated for protection. This umbrella has a pulley and pin system that is easy to use with heavy duty 9 oz. marine grade fabric that is made to withstand outdoor commercial use. The triple stitched pockets that hold the cover are constructed not to tear in a heavily used commercial environment.