bikini). Women's swimwear may also cover the midriff as well. Women's swimwear is often a fashion statement, and whether it is modest or not is a subject of debate by many groups, religious and secular. Competitive swimwear is built so that the wearer can swim faster and more efficiently. Modern competitive swimwear is skintight and lightweight. There are many kinds of competitive swimwear for each gender. It is used in aquatic competitions, such as water polo, swim racing, diving, and rowing. Wetsuits provide both thermal insulation and flotation. Many swimmers lack buoyancy in the leg. The wetsuit provides additional volume at a lower density and therefore improves buoyancy and trim while swimming. It provides insulation between the skin and water which reduces heat loss. The wetsuit is the usual choice for those who swim in cold water for long periods of time, as it reduces susceptibility to hypothermia. Some people also choose to wear no clothing while swimming; this is known as skinny dipping. In some European countries public pools have naturist sessions to allow clothes-free swimming and many countries have naturist beaches where one can swim naked. It is legal to swim naked in the sea at all UK beaches. It was common for males to swim naked in a public setting up to the early 20th century. Today, skinny dipping can be a rebellious activity or merely a casual one. Accessories Ear plugs can prevent water from getting in the ears. Noseclips can prevent water from getting in the nose. However, using noseclips in competitive swimming can cause disadvantage, so many competitive swimmer choose not to use one. For this reason, nose clips are primarily used for synchronized swimming and recreational swimming. Goggles protect the eyes from chlorinated water, and improve underwater visibility. Tinted goggles protect the eyes from sunlight that reflects from the bottom of the pool. Swim caps keep the body streamlined and protect the hair from chlorinated water, though they are not entirely watertight. Kickboards are used to keep the upper body afloat while exercising the lower body. Pull buoys are used to keep the lower body afloat while exercising the upper body. Swimfins are used in training to elongate the kick and improve technique and speed. Fins also build upper calf muscles. Fins provide a significantly greater and more efficient conversion of muscle power to thrust than available from the feet, and allow the