This reversible hat works twice as hard to keep you warm and looking good. A Cocona poly-blend fabric on one side wicks away the sweat and provides UPF40+ sun protection while a lightweight fleece Cocona blend on the other side keeps out the chill. What makes us "CoCo" for these hats is that the Cocona fabric is made from mashed up pulp of coconut shells. Really! These hats are also machine washable and will look great on or off the water.