These Super Dielectric Overshoes are made from an ozone resistant yellow rubber. The deep heel provides extra safety when climbing ladders and poles. These overshoes are 100% waterproof with a fabric lining. The sole is an anti-skid bar tread. The outsole of these overshoes and boots have been tested to meet the electric hazard requirements of ASTM F2413. Fitting tip for Super Dielectrics: Standard sole, order one full size larger than the boots to go over. Heavy lug sole, order two sizes larger than the boots to go over.