The Costa Del Mar Blackfin 400G Polarized Sunglasses won't slip off your face when it counts the most. Even when you have gallons of brine in your face and 600 pounds on your hook. The Hydrolite co-injected lining takes care of that, and the flexible frame means serious comfort. The Costa Del Mar Blackfin pushes the edge in sunglass performance--so you can push it everywhere else.