FlexGround UltraFlex is the highest quality, longest lasting rubber safety surfacing on the market. UltraFlex is poured using the same two-layer system as FlexGround Standard and EnduraFlex, but utilizes a smaller (.5mm) granule TPV for the top surface wear course. Elevated urethane ratios bind the smaller granules together for a superior product, which boasts the best elongation and tensile strength in the industry.