DetailsSmartwool Size Chart 100% Merino. 100% capable. The Women's Merino Base Layer Bottom is always ready for what's ahead and what's next. With a fit updated to improve functionality while enhancing aesthetics for a range of body shapes and a flatlock seam construction designed to minimize chafing, comfort is never in question. Get yourself a pair or two of the best base layer pants and conquer the cold with more confidence than ever.