Harmony Yoga Mats utilize the non-slip properties of open cell, natural rubber (a renewable resource tapped from rubber trees). Not only can you say goodbye to slipping on your practice mat, even if it gets wet with perspiration, but these high performance mats provide outstanding resilience, resistance, and cushioning. These PVC-free, biodegradable mats are made from 99.5% natural rubber and contain no ozone depleting substances.