The simplest shoes are made from a single-density polyurethane outsole. Polyurethane soles must have two tasks: first, must feel comfortable, and the sole is light, second, is also a very important point, that is, safety problems, such as anti-skid. In fact, it is difficult to combine these two functions, and in most cases only one of them can perform the correct performance. The density of polyurethane soles is mostly around 0.8g/cm3, usually used in the casual footwear industry.
The production of single-density shoes is very simple and effective, but the products produced are still high-grade commercial shoes.