Material:EVA Material:EVA, carbon fiber, polyester heating material::carbon fiber heating element. size::S(36~38), M(39~41), L(42~44) batteries::rechargeable,AA batteries time of keep warm::H -3 hours, M-5hours, L- 7hours. li battery:3.7V/1400MAH product size:29.5X9.5x1cm ( L) certification::CE, ROHS Show More