Synthetic rubber is also divided into wear-resistant rubber, environmental rubber, air rubber, viscous rubber, hard rubber and carbon rubber. Wear-resistant rubber has excellent wear resistance and toughness, so it is very durable. This rubber material is generally used on the soles of tennis shoes. Also known as recycled rubber, this rubber outsole contains up to 10% recycled rubber, mainly for environmental protection.

The carbon element is added to the common rubber material, which makes the rubber more tough and wear-resistant. Most running shoes use this kind of rubber, and the BRS letters are left on the back part of the sole of the running shoes to indicate that the carbon rubber is used in the outsole.