Bekina boots from UltraSource achieve both durability and comfort with millions of tiny air bubbles that form to your feet, providing insulation in extreme temperatures down to -4°F. These modern polyurethane boots are lined with a slip-resistant rubber underlay and include removable felt insoles that wick away moisture. A pair of polyurethane boots is approximately 2.25 lbs. lighter than PVC boots, reducing fatigue and giving you more energy at the end of the day.