A personal flotation device (abbreviated as 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. Designs differ depending on wearing convenience and level of protection. (source)