For both boys and girls, Smartwool's 100% merino wool interlock bottoms are great winter under-layers for added warmth. They feature a covered waistband and flatlock seams that eliminate chafing. Side panels provide a smooth, tailored fit. Naturally odor-resistant and itch free, your kids will love these warm and comfy bottoms. They make great winter pajamas and you can even wash them with the rest of your clothes. So, that must be why they call it Smartwool! Designed to go with the Smartwool Midweight Crew Shirt.