The sole is the key part of the shoe that comes into direct contact with the surface. Its main function is to provide traction, protection and support to the foot. The materials used to make the sole, such as rubber, EVA (ethyl vinyl acetate) or TPU (thermoplastic polyurethane), are selected based on their durability, flexibility and shock absorbing ability. Choosing the right outsole depends on the type of activity, terrain and personal preference.