For refrigerators, washing machines, pumps, stokers, woodworking machines, etc. Do it belts feature Concave Sidewalls to give the belt full-grip on the pulley sides. Rubber Filled Cords prevent separation of cores and rubber. Protective Fabric Jacket (made from special compounded rubber stock) for silent running, oil and heat-resistance. Thanks for shopping Hipp Hardware Plus's Online Store for all your DIY and Home Improvement needs. Remember Hipps Help!