These heat-moldable liners are now pre-molded to speed up the customization process. They are designed to have an overlap entry instead of a tongue to give them the necessary ankle support without the requirement for additional ankle reinforcement. This overlap design is also the only total contact liner, which means that, unlike foam injected liners, the liners are in contact with the entire surface of your foot. This design has been proven to offer the best performance and the most comfort for all users. Not only do you get a truly customized fit, these are much warmer and lighter than traditional stock liners to include injection liners to provide superior warmth and will decrease the weight of your boots by around 1 pound (0.5kg). What makes Intuition Liners Ultralon foam unique is their molding processes which are made from thermo-forming closed cell foam. This foam consists of millions of tiny cells, or bubbles, which are created by pouring measured amounts of the mixed ingredients into a two-piece mold which is sealed and heated under tremendous pressure. The material is heated slowly and evenly to a specific temperature and pressure, and then is allowed to cool to ambient temperature before the mold is opened and the foam is removed. This process results in very uniform cell structure and a very high percentage (70% - 80%) of cross-linkage between molecules in each cell wall. This high percentage of cross-linkage between the cells means that the foam does not allow gases in each of the tiny bubbles to migrate to the others, which would change the shape of the foam. The membrane between the cells is also treated with chemical filler which creates a more homogeneous membrane. All of this results in the ability to mold the foam into a specific shape when heated, which the foam will retain when cooled with reduced heat-related shrinkage, high quality memory, and resistance to packing out. This foam can also be re-heated and molded more than once without damaging its structural integrity or quality.