ALPENHEAT Heating Insoles Lithium Standard Model: IS6 Standard insole with integrated heating element for ALPENHEAT Lithium Boothheaters: Large heating element 43 cm² in the forefoot 3mm insoles, ready to be cut to size: EU 35.5 – 48.5 Fit in any shoe or boot Robust wire heating element High quality insole, breathable and moisture absorbent