Sorel Women's Helen of Tundra Boot. Featuring a waterproof upper made of full-grain leather with soft felted wool and a full-front zip closure. Sorel uses 100g Thinsulate insulation and a fixed 3mm lining for the interior of the Helen of Tundra II boot and a handcrafted vulcanized rubber shell with herringbone outsole for grip. Seam-sealed waterproof construction Waterproof full-grain leather upper 100g Thins late Insulation with 3mm felt lining Handcrafted waterproof vulcanized rubber shell with herringbone outsole Full front YK zip closure