SmartWool Base Layers - SmartWool Womens NTS Midweight Crew Base Layer - Black :: Women > Thermals. Heat Transfer Logo: To left sleeve Material: 100% Merino Wool Form fitted: Body enhancing fit perfect for layering Women's base layer Machine washable Interlock Knit: Breathable fabric construction with UPF 50+ treatment Shoulder Panels:No top shoulder seams for a comfortable fit Women's base layer Material: 100% Merino Wool Machine washable Flatlock Seam Construction: Eliminates chafing for all-day comfort Form fitted: Body enhancing fit perfect for layering Interlock Knit: Breathable fabric construction with UPF 50+ treatment Shoulder Panels:No top shoulder seams for a comfortable fit Heat Transfer Logo: To left sleeve Flatlock Seam Construction: Eliminates chafing for all-day comfort