Polypropylene thermals are great for hunting, fishing, camping, skiing, work, or any other cold weather outdoor activity. Polypropylene is a unique material that is perfect for frigid climates. Polypropylene has the lowest thermal conductivity of any traditional apparel fiber. Dry polypropylene fiber does not absorb moisture; it's unique vapor transfer ability moves moisture away from skin and keeps you dry no matter what you may be doing. This rashguard is perfect for divers who do not need a thick millimeter suit in shallow warm water areas.