A life jacket, also known as a personal flotation device (PFD), is a wearable device that is designed to keep a person afloat in water. Life jackets are typically made of foam or inflatable chambers, and they come in a variety of sizes and styles to fit people of all ages and body types. Life jackets are an important safety device for anyone who participates in water activities, such as swimming, boating, and fishing. They can also be helpful for people who work around water, such as lifeguards and dockworkers.
 Life jackets work by providing buoyancy, which is the force that helps things to float. When a person is wearing a life jacket, the buoyancy of the jacket helps to keep them afloat, even if they are unconscious.