Fortress SockPro The world's first insulated sock, featuring patented Aeris 250 ½ insulation throughout. Our advanced design maximizes heat retention while comfortably compressing inside any shoe or boot, making it the warmest sock available. "Do NOT Wear near Fire" Pro Tips for Ultimate Warmth: Keep your core warm with our BasePro or Jacket for full-body heat retention. Stay hydrated to help regulate body temperature and maximize your comfort. For the best performance from our socks , we recommend pairing them with our BasePro layers or jackets to maximize warmth . We're also updating our online info to emphasize that keeping your core warm first is the key to preventing cold hands and feet . NEW IMPROVED DESIGN AND FIT Men's Sizing: S: 5-6, M: 6-8, L: 9-10, XL: 11-13. Women's Sizing S: 5-7 M: 7-9 L: 10-11 PLEASE NOTE: For those with sensitive feet, we recommend wearing a thin wool or Merino non-cotton sock as a first layer under the SockPro . This additional layer will enhance comfort and provide an irritation-free experience, as interior seams may sometimes cause discomfort. AERIS INSULATION (Placement) Materials: 80% Nylon / 20% Spandex 4 way Stretch Weight 4 oz Dimensions 1 × 2 × 10 in SIZE Small, Medium , Large ,XL
