Developed from 300,000 feet and 15,000 shoes, the Sidas socks offer a perfect fit between your feet and your shoes. This heated sock is designed for skiers who suffer from cold feet. An invisible heating element on the outside of the sock gives off a soft and constant heat under the front of the foot for optimal comfort. Natural wool combined with technical fibres ensure temperature regulation and effective sweat wicking. This compressive sock also gives you greater sensation and precision when you practise your sport.NOTE! Batteries not included TECHNICAL FEATURES: HEATING ELEMENTS : Distributes gentle, constant and uniform warmth; KNEE LENGTH : Adapted to ski boots; HYBRID COMPOSITION : Regulates temperature & wicks away perspiration effectively; FIRM FIT 15-20 mmHg : Greater precision & sensation; 2 THICKNESSES LV/MV : Available in low or medium volume to adapt to your foot & shoe fit; SYNERGY FIT CONCEPT : Designed for an optimal fit in synergy with your shoe, insole & feet : - No padding under the sock and inside the shoe, - No-yarn towards the skin, - Anatomic shape right & left