Arcteryx has done it; they have created the ideal baselayer for any activity when they Built the Arcteryx Rho LTW Zip for Girl.Constructed with soft, itchless, stretch knit merino wool, the Rho LTW insulates even when completely saturated, regulates temperature far better than a synthetic baselayer, and resists odor, even on a week long backcountry trip.A collar zip makes for easy layering and great ventilation and the form fitting silhouette and nolift gusseted underarms give you the freedom to move without restriction.