Because Aerogel is the world's best and lightest insulation material it can maintain the temperature of your feet at about 72-degrees at all times (winter & summer, indoors or outdoors).
These insoles are made to the shape of the sole of an average foot, therefore, one size can be used by men, women and children. The exterior covering is an envelope made of clear re-movabble plastic film that is a rectangular shape. In use the covering is flexible enough to shape itself around the inside of your shoe or boot and thus, can fit the inside of your shoe. These insoles can be trimmed if need to make smaller size. They do not wear out. Insulation quality remains constant at all times.