The eKO Mat is a natural yoga mat made from sustainably harvested tree rubber. Unlike other rubber mats available today, the foaming agents used to create the eKO are non-toxic. What this means is that no toxic chemicals have gone into the manufacturing process to soften the rubber. Additionally, instead of using synthetic polyester for reinforcement, we have chosen to use a blend of polyester and natural cotton. According to both customer feedback and published yoga mat reviews, the eKO Mat is a high performance mat that is also good for the environment.