The men's Polarmax Core 4.0 Crew Baselayer is a highly moisture wicking, and breathable, baselayer that will keep you cool during hot days and warm during cold days. Thanks to the Acclimate® Dry Moisture Wicking material, you will stay drier than ever before. The 10% Lycra material keeps this base layer stretchy and comfortable for better muscle support and mobility. The crew design increases airflow during hot days. Whatever your activity may be, use the Core 4.0 Crew for added support and warmth.