Swimming for the persons with a visual impairment is a sport that has been practiced for years. Swimming offers many benefits since it can be enjoyed and practiced from the junior level well into the senior years. Over 70 swimmers from 25 countries participated at the 1996 Atlanta Paralympic Games. Competitive Swimming follows the Fédération Internationale de Natation – International Swimming Federation (FINA) rules with some allowances for lack of vision. Visually impaired swimmers compete in three classes - B1, B2, or B3 as defined by the International Blind Sports Association (IBSA). B1 swimmer, being totally without sight, requires more considerations than B2 or B3 swimmers. Tapping is the most important assistance required. This is a method of informing the swimmer when he or she is reaching the end of the pool and must execute a turn or make a final touch. Sighted partners (tappers) are positioned at each end of the pool and using a rod with a firm butt; safe tip touches or "taps" the swimmer. Allowances are also made for B1 swimmer who may be too close to a lane line to execute technically correct arm strokes in butterfly or touches in butterfly or breastroke. A team coach directs the takeover for relays. While most of the fully sighted swimmers choose to wear swim goggles B1 swimmers are required to wear blacked out goggles. B2 and B3 swimmers can compete under FINA rules without further adaptations however due to some light conditions they do have the option of being tapped.