These are experienced lifeguards or lifesavers who have undergone additional training to train and assess. Surf skis were later used by lifesavers to rescue drowning swimmers. Since 1907, surf lifesavers have rescued over 650,000 beachgoers. Lifesaving also refers to sport where lifesavers compete based on skills, speed and teamwork. Surf lifesavers must be competent swimmers and skilled in rescue techniques, resuscitation and first aid. Surf Lifesavers patrol various beaches in New Zealand. Three main types of breaking waves are identified by surfers or surf lifesavers. However surf lifesavers and the Westpac Life Saver Rescue Helicopter Service attend to incidents. Surf lifesavers in Australia are colloquially known as "Clubbies". Unlike senior surf lifesavers, the majority of them do not patrol the beaches. The beach is not patrolled by lifesavers. Lifesavers are volunteers and usually stationed at a club house. Lifesavers who are on patrol wear red and yellow cloth caps on the head. The surf lifesavers have the use of a building with a first-aid room. Pool lifesavers are trained to scan the bottom for the situation shown.