When it comes to keeping children's feet dry and warm, the Southpole 4 is worth a look. Both the upper material and the flexible outer shell are waterproof, providing excellent protection against moisture along with the sealed seams. The thermal properties come from the interchangeable 6 mm thick Zylex insole with moisture-absorbing inner lining. Kamik's patented Zylex technology is the ultimate innovation for excellent heat and moisture management. The revolutionary three-layer design wicks sweat away from the feet while retaining body heat inside and keeping the cold out. With additionally reinforced seams and heel protection, long durability is guaranteed. For size adjustment, there is a bungee closure around the midfoot, and the snow collar can also be adjusted with a bungee closure.