How does the ToastyLiner Sleeping Bag Fleece Liner warmer work?

The concept is similar to a hot water bottle. Heat placed at critical points on the body radiates warmth as blood circulates. For example, Emergency Medical Technicians put a bottle of warm water between the legs of a hypothermia victim to raise the core body temperature from the inside. The ToastyLiner Sleeping Bag Liner utilities this idea by strategically placing eight pockets located to heat different body zones. The camper can use some or all of these to insure a warm night’s sleep in frigid temperatures.

Here’s how easy it is to use. About an hour before bedtime, activate each warmer by shaking it vigorously, then slip it under the first layer of the pocket and behind the second layer. Once the warmer is inside the pocket, it won’t come out during the night. The warmers pre-heat the sleeping bag and the fleece feels cozy as one crawl in. So, you will have no more shock of cold nylon when entering the bag.