Made from an ozone resistant yellow rubber , 100% waterproof. The construction is hand-layered in full-cut patterns to fit over work boots. The fabric lining makes them easy get on and off. The sole is an anti-skid bar tread. The outsole and boots have been lot tested to 20,000 volts to the electrical hazard requirements of ASTM F2413-05. This Storm Rubber comes in Whole and Half Sizes 7-12, Whole Sizes 6, 13-17. Sizing: If wearing with Tennis or Gym shoe, order same size. Work Boot, one size up. Steal Toe, two sizes up.