Rubber sole refers to the sole made of rubber. The rubber sole material can be roughly divided into natural rubber or synthetic rubber. The advantage of natural rubber is that it is very soft, has excellent elasticity, can adapt to all kinds of sports, and plays a role in shock absorption, but the disadvantage is also very obvious that it is poor in oil resistance, ozone aging resistance and heat and oxygen aging resistance. Indoor sports shoes are mostly made of natural rubber.

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.