The endura transmission ii womens long sleeve base layer has been made from a polypropylene yarn for superior moisture transfer and rapid drying this works well as it keeps you dry and prevents discomfort by wicking sweat away from your skin the strategically placed body mapped mesh zones have been used to increase airflow and breathability to regulate your body temperature and prevent you from overheating this women39s base layer has an antibacterial finish to keep both you and the base