The Thermopad series of heaters are air activated. They bring a natural heat thanks to the unique composition of the contents. They heat up to 45 °C (113 °F) and keep an average temperature of 37 °C (98.6 °F) for up to 6 hours.
The body warmer is intended for placement on the lower back where it distributes the heat to that area.
This version sold as a handy 5-pack.