Therm-Ic provides warmth right where you need it moston the soles of your feet. Just combine these insoles to a ThermIc C-Pack of your choice for a toasty outdoor experience. - The 3D-contouring supports the arch of the foot and prevents muscle fatigue. - Supportive heel and EVA foam ensures constant shock absorbtion. - Cables reach to the top of skiing boot shafts and many other kinds of boots - Compatible with separately available extension cables, enabling battery placement on belt etc. - The insoles have a 2 cm trimming possibility: just use a pair of regular scissors to trim down to your boot size - Sizes: - XS = 35 - 36 - S = 37 - 38 - M = 39 - 41 - L = 42 - 43 - XL = 44 - 45 - XXL = 46 - 48 Compatible with C-Pack battery sets. Not compatible with older Therm-Ic batteries or extension cords. The connector model was changed in Fall 2017. The package contains a pair of insoles. Batteries sold separately.