Base layers usually function in two ways. First they help with moisture management, and second, they minimize abrasion from your outer-layers. The Gore Bike Wear WindStopper Thermo Women's Long Sleeve Shirt has a third purpose, though. Its wind-stopping and warming properties keep icy wind from blasting through your jersey. For the construction of the base layer, Gore Bike Wear made sure to protect the areas most prone to exposure with its patented WindStopper membrane. And in case you were wondering, these areas include the chest, shoulders, and kidneys. The layer on top of the WindStopper membrane is a moisture-wicking, polypropylene fabric that's been blended with both elastane and nylon. This blend lends itself to a conforming fit, while also efficiently managing moisture. In terms of comfort, Gore made sure to use a minimal amount of seams throughout the construction. However, where necessary, it incorporated flatlock stitching to eliminate the threat of chafing. The Gore Bike Wear WindStopper Thermo Women's Long Sleeve Shirt is available in six sizes from X-Small to XX-Large and in the colors White and Black.