An all-season favorite the Smartwool Women’s Classic All-Season LS Merino Base Layer features Core Spun technologymdashwhich is Merino wrapped around a nylon core for added durability while still keeping the comfort of ultra-soft responsibly sourced Merino next to skin. Raglan sleeves eliminate shoulder seams for perfect comfort under a pack and smooth merrow stitching wraps from side to front to keep you looking as good as you feel.