A specialized kind of wetsuit, with a very smooth (and somewhat delicate) outer surface known as "smoothskin", which is the original outer surface of the foamed neoprene block from which the sheets are cut, is used for long-distance swimming, triathlon competitive apnoea and bluewater spearfishing. These are designed to maximize the mobility of the limbs while providing both warmth and buoyancy, but the surface is delicate and easily damaged. The slick surface also dries quickly and is least affected by wind chill when out of the water.