Product Info All you need. The Winter Custom Comfort is a flat insole, 100% customizable to the morphology of the foot, thanks to the Custom technology, by thermoforming. Insoles for sports veteran in search of a maximum performance, it consists of an upper comfort foam antibacterial (Ionfoam 2.5mm) and a ball of foot shock absorption area for maximum cushion in any boot wether it be for snow or summer.