Helly Hansen Men's HH Active Flow Long Sleeve Base Layer Shirt 65% Polyester,35% Polypropylene Imported Advanced moisture wicking Lifa technology in a versatile men's base layer ideal for any activity HH Active is an advanced construction combining Lifa Stay Dry Technology and fast wicking fibers, making it ideal as an all year activity base layer Relaxed fit, making it just as great to wear as a casual piece Polyester exterior, Lifa Stay Dry technology inner Flatlock stitching