lifebuoy

thumb|Lifebuoy with emergency light on a cruise ship thumb|A lifebuoy floating on water

A lifebuoy or life ring, among many other names (see § Other names), is a life-saving buoy designed to be thrown to a person in water to provide buoyancy and prevent drowning. Some modern lifebuoys are fitted with one or more seawater-activated lights to aid rescue at night.