The Women’s Siren 4 Thermo Mid Zip Waterproof boot is engineered for winter adventures, offering exceptional function and all-day comfort with a women’s-specific fit. It features 200 grams of Primaloft Gold Eco Series synthetic insulation for reliable warmth, and a SOLARCORE Aerogel insole that delivers superior underfoot warmth while remaining flexible and ultra-thin. The boot’s waterproof full-grain leather upper, coupled with a waterproof membrane, effectively keeps water out while allowing moisture to escape. For enhanced winter traction, the Vibram Arctic Grip™ All-Terrain outsole provides durability and versatility, making it perfect for tackling diverse winter conditions. Merrell Womens Siren 4 Thermo Mid Zip Waterproof Features: Merrell Womens Siren 4 Thermo Mid Zip Waterproof Features: Heavy-duty, Waterproof, YKK zipper for easy on and off Protective and abrasion resistant rubber toe cap Cleansport NXT™ treated for natural odor control FloatPro™ Foam midsole for lightweight comfort that lasts Waterproof full grain leather and knit upper 100% recycled laces and webbing 100% recycled fleece lining 100% recycled mesh footbed cover 5% recycled PU removable footbed Stack Height: 28.5-20.5mm Drop: 8mm Lug: 5mm Half pair weight: 1lbs-3.04oz, 540g