emission of far infra-red (fir) radiation and maximization of thermal efficiency by impregnating charcoal layer along with high quality tourmaline stones. it is equipped with emission of far infra-red (fir) radiation and maximization of thermal efficiency by impregnating charcoal cotton layer apart from 30 mm dia tourma ceratonic stone balls. its really convenient to carry on a vacation or to the place of sleeping as it is portable and easy to store. added gift of 3&9 jade thermal massager multiplies the health benefits .