It’s wicking, warming and ergonomic qualities make it a versatile, year-round, half-zip, go to tech tee. Wear it as a baselayer in the winter, or as a standalone during workouts and recreation in the spring and fall. Omni-Heat™ thermal reflective Omni-Wick™ 4-way comfort stretch This product incorporates an antimicrobial treatment intended to protect the product from bacterial growth. The active biocidal substance is: pyrithione zinc. Ergonomic seaming Flatlocked construction Thumb holes Centre Back Length: 29.125" CompositionOmni-Heat™ Reflective Anytime Stretch Jersey 85% polyester, 15% elastane Columbia Men's Omni Heat Midweight Stretch Long Sleeve Half Zip Baselayer (Black 011)