This premium stack chair is made of heavy duty, 13/16" tubing, 18 gauge high carbon steel that will not bend out of shape. 2" high resiliency, high density 1.8 lbs foam over 5/8" plywood highgrade. All plywood seat and back with tab support back. Waterfall style seat for extra comfort. Side bars aligning chairs when stacked adding extra protection to frame. Under seat reinforcing bars. Epoxy powder coated assuring chip and corrosion resistance. Handhold for easy moving. Stacks 13 high.