In cooler waters, paddlers often wear a wetsuit or drysuit. In the early 1970s Gul Wetsuits pioneered the one-piece wetsuit named as the steamer. Wetsuit gloves are also commonly worn with dry suits. A "shortie" wetsuit may be worn over a full wetsuit for added warmth. The wetsuit reduces density and therefore improves buoyancy while swimming. Free divers may also use weights to counteract buoyancy of a wetsuit. Some triathlon sanctioning bodies have placed limits on the thickness of the wetsuit material. These suits have special heating panels integrated in the back of the wetsuit. Several styles of wetsuit boots are commonly used for kayaking. In cooler waters, a wetsuit may also be worn. Most popular with warm-water/wetsuit and travelling divers. These shirts can be worn by themselves, or under a wetsuit. A "skin" may also be worn under a wetsuit. Without a wetsuit, Victoria suffers severely from the cold water. Different types of wetsuit are made for different uses and for different temperatures.