After skiing for many years I have seen a lot of different ideas about what is the best way to keep your feet warm. And let me tell you wearing four pairs of socks is not going to keep your feet warm! When you wear that many pairs of socks it makes your feet so big around that when you put your foot in the boot the blood circulation is cut off, this = cold. The key to warmth is blood circulation. The boot liner is made out of foam and material that is not only good for padding but warmth also. So next time you go skiing get a good thin wool sock (not cotton), from your local ski shop and let the blood flow in the feet!