We're not superheroes, born with speed, strength, and an Indurain esque resting heart rate of 28 beats per minute. We have to work to get there, and that work is a year round process if we want to stay at our best. When the year gets cold, we can't afford to stop, so out comes the Craft Extreme Underpants Base Layer and up goes our fitness. These thermals are made from six channeled and hollow core synthetics for three reasons. The hollow core provides insulation by creating pockets of warm air between you and the elements, the six channeled fabrics increase effective surface area for better moisture management, and they're super stretchy. The seams are external to avoid chafing while you're trying to super size your winter training program. The Craft Active Extreme Underpants Base Layer is available in five sizes ranging from Small to XX Large in the colors Blackplatinum and Blackred.