ACHIEVE THE HIGHEST DEGREE OF WARMTH. This is a product where we deviate from our light is good philosophy. Some days you just want extra protection for your feet, and the Estremo provides it. Weve used a micro injection covering on the lower portion of this thermal windproof and water resistant bootie that gives extra warmth and durability. Then we added a waterproof zipper, 3M reflective piping, and an extra durable sole. And of course we made it so that youll be getting compliments throughout the ride.