In 1997, Lake invented the first true winter-specific cycling shoe, the MXZ300. The unique boot shape and construction allow us to trap warm air, which is the best insulator for any type of footwear. The pattern is designed so it doesn't restrict blood flow to the foot, as it is your foot that creates the heat the boot is designed to trap. Keeping that trapped heat in as air allows two things to occur: your foot stays warm and dry. Because the MXZ305 uses a highly breathable leather upper and temperature-regulating, wicking lining, sweat is transferred away from the foot so that it does not freeze against it, keeping your foot comfortable. The MXZ305 is the fifth generation of that legacy and continues to be the best of the best as the top winter-specific cycling shoe of choice. Sizing Suggestion: For use with winter weight socks we recommend ordering 1-1.5 sizes up from your usual Lake Cycling shoe size.