The Men's Smartwool Merino 250 Baselayer Pattern Crew is a tried and true layering piece that has been updated to improve functionality and aesthetics. An interlock 100% merino wool knit offers comfort, breathability, thermoregulation and odor resistance. Shoulder panels eliminate top shoulder seams while the flatrock seam construction minimizes chaffing while wearing the Merino 250 Baselayer Pattern Crew.