Sorel Caribou Youth THE ICON The one that started it all, Caribou features a fully seam-sealed waterproof construction to keep the elements out. The tough rubber sole provides extreme traction in the snowiest days. MIDSOLE: 2.5 mm bonded felt frost plug. UPPER: Waterproof nubuck leather upper. Seam-sealed waterproof construction. INSULATION: Removable 9 mm washable recycled felt inner boot with Sherpa pile snow cuff. OUTSOLE: Handcrafted waterproof vulcanized rubber shell with Sorel aero-trac non-loading outsole.