A wetsuit is a protective garment use for watersports such as scuba diving, surfing, windsurfing, kitesurfing and triathlon. A modern, warm-water wetsuit is mostly made from thin open-cell neoprene, which provides limited thermal protection for activities in cold water, but protects the wearer in warm water from sun exposure. Cold-water wetsuits are built differently, have seams which do not leak, and provide good protection from cold water (to about 45°F, or 8°C) for up to 60 minutes in shallow water (less than 10 meters or 33 feet). A wetsuit is usually lined with a nylon fabric to strengthen it and make it easy to put on and take off. Some newer wetsuits, usually marketed as "superflex," contain spandex in addition to neoprene to allow the suit to stretch (the panels of a wetsuit of this type typically contain 15-20% spandex). This counteracts neoprene's tendency to shrink with age; it also allows for some changes in the wearer's size without making the suit uncomfortable.