Craft introduced its 'Keep Warm' collection of base layers for athletes who train, race, and work in cold conditions. The Warm Crewneck Women's Long Sleeve Base Layer is an integral part of this line, as it was developed with Craft's proprietary blend of technical materials in order to keep you both protected and comfortable while out in the elements. Made from Alpaca Wool Craft learned that specific areas of the torso need different weights of fabric in order to successfully manage core body temperature. Solidifying this, the 'body-mapping' research that Craft conducted showed that various zones of the torso benefit from applying both thicker and thinner compositions of insulating yarns. To achieve this, Craft used its hollow-fiber C131 polyester/polyamide fabric. This material is made from both lightweight and warming thermal yarns that use a 3-D knit construction. By targeting these specific areas of the torso with different weights of this fabric, Craft was able to build a base layer that provides optimal thermoregulation and overall comfort. The Warm Crewneck's seamless torso construction and smooth flatlock stitching ensures that the base layer comfortably forms to your body without any irritation or abrasion. The highly elastic fabrics used to construct the Active Extreme provide a smooth anatomic fit that moves with you underneath your additional clothing layers. Size Small 15.5” underarm to underarm 24” length PreOwned