This thing is PURE CONCRETE.  IT IS SOOOOO HEAVY. It came broken at first and I wasn't even able to haul the pieces myself. Wayfair's customer service was excellent and called a hauler to pick up the pieces and remove it from my front porch. It was replaced and arrived in a timely manner. It took two people to get it to the patio (we rolled it on its edge) and it was a BEAST. BUT it's super strong and the wheels are excellent. My umbrella definitely won't blow away. EVER.