This purpose is theoretically fulfilled by the buddy assisting the diver to kit up, checking that the diver's equipment is correctly assembled and mounted, assisting the diver into the water where appropriate, checking for leaks, monitoring gas usage, providing an alternate breathing gas supply in case of an emergency, performing a rescue if the diver is unable to manage an emergency, and assisting the diver out of the water after the dive if appropriate. This system can mitigate high-risk emergencies when performed to the standards. This is not a controversial issue. This level of assistance requires the buddy to be familiar with the diver's equipment in detail, including the adjustment of harness and emergency release of weighting systems, control of inflation and dump valves, siting and attachment of secondary demand valve, knife and any other safety equipment. Recreational divers may be trained in some or all of these skills depending on their certification. The buddy system is not considered sufficient on its own, Dive planning, medical and physical fitness to dive, suitable and correctly functioning equipment, appropriate surface support, skills, experience and knowledge are all part of the diving safety system. To be fully effective, the buddy system is applied to an agreed dive plan, with effective communications, the willingness and ability to assist each other in all reasonably foreseeable circumstances associated with the dive plan, and the will to follow the dive plan.