ThermiPet pain relief products are unlike any other therapy delivery system on the market today. Made using a patented Theramics (Thermal Ceramic) compound that utilizes a synchronized blend of all-natural, ceramic clay and non-toxic oils. This compound creates the ideal thermal transfer source to absorb heat or cold and then slowly releases it at a stable temperature over an extended period—cools in the freezer, heats in the microwave. Theramics capitalizes on the efficiency of radiant energy to create deep penetrating, therapeutic pain relief. This unique compound is safe, easy to use, remains flexible and is highly efficient in the treatment of many pain discomforts such as arthritis, sports injuries, muscle pain, and joint stiffness. Available in two sizes, it is reusable, portable, and includes a washable blue cloth cover with one Velcro® strap on the small and two straps on the large pad. This item is not chew resistant; please follow instructions for safe use and do not leave unattended with pet.