Hot & Cold Foot Relief Roller is designed to soothe pain associated with Plantar Fasciitis (PF) as well as heel spurs and other common aches and discomforts. It has an ergonomic shape that conforms to the curve of your foot plus a textured surface that comfortably massages. Your roller massager is powered by a hot/cold technology, so you can expect it to stay hot or cold for as long as 20 minutes of therapy. Use it for quick relief of foot pain or relaxation. For warm massage: Dip in hot water. Do not microwave. For cold massage: Place in freezer until desired temperature is achieved.