Under Armour fishing collection shirts are designed to keep you cool, dry and light while you're on or near the water. The Flats Guide II Shortsleeve is made with Under Armour's AllSeasonGear fabric that has a moisture transport system to deliver core temperature regulation and maximum breathability. The longsleeve and shortsleeve t-shirts are made with Under Armour's HeatGear fabric which keeps you cool and dry in the warmest conditions, and dries quickly so you stay comfortable all day. Both style shirts offer UPF 30+ ultraviolet protection to protect your skin from the sun's harmful rays.