A body warmer that uses air to generate heat can reach 40°C. There will be eight hours of natural heat. A large 13 cm by 9.5 cm heat patch can be put securely and fitfully over an area, like the neck or shoulder.a pleasant feeling of warmth. There isn't any perfume or medication in the formulation. Its odorless, thin, and straightforward design makes it easy to fit into a pocket or purse and allows for anytime, anyplace use.