Rubber.
TPE Material, from which the fitness exercise mat is made, is a thermoplastic elastomer with both thermoplastic and elastomeric properties, which is essentially a combination of rubber and plastic. The material is characterized by high durability. TPE mats do not lose their shape, are environmentally friendly, and do not deform. TPE mats are stable and non-slip. These mats are great as a yoga mat, a mat for Pilates exercises, and for aerobic training.