The PolarMax Micro H1 Long Sleeve Crew is a great all year base layer. This top provides a relaxed fit that stretches and has flat seams for more comfort. It is also quick to dry and breathes great. This top is made with Acclimate Fresh/Anti-micorbial to aide in odor control. Warm crew with relaxed fit and flat seams. Stretches for comfort. Quick Drying. Acclimate Dry Moisture Wicking and Acclimate Fresh Anti-Microbial. Weighs 4.5 oz./ sq yard. Material: Polyester, Lycra.