Personal flotation device - Wikipedia
A personal flotation device (PFD; also referred to as a life jacket, life preserver, life belt, Mae West, life vest, life saver, cork jacket, buoyancy aid or flotation suit) is a piece of equipment designed to assist a wearer to keep afloat in water.The wearer may be either conscious or unconscious. PFDs are available in different sizes to accommodate variations in body weight.