NWT SmartWool Thermal Ribbed Base Layer Turtleneck Merino Wool Long Sleeve Size:Large About SmartWool Thermal Ribbed Base Layer Turtleneck - Merino Wool, Long Sleeve Closeout. Warm thermal merino wool fabric and a movement-friendly fit make SmartWool's ribbed base layer turtleneck a warm choice to add to your cold-weather rotation. Itch-free merino wool is temperature regulating, moisture wicking and odor resistant Rib-knit design Turtleneck Raglan sleeves Curved hem Regular fit