A buoyancy aid differs from a life jacket in its conception and flotation characteristics. As its name suggests, it does not by itself keep the wearer at the water's surface. The user must swim to stay afloat.
The buoyancy aid is used in calm waters, coastal sailing and seashore activities.
The buoyancy aid does not guarantee that the wearer's head will remain above water. Thus, the mouth and nose of an unconscious person in the water may be submerged. It has a buoyancy rating of 50 N. On the other hand, a life vest ensures that the wearer's head remains above water, face up. Its buoyancy rating is 100 N, 150 N or 275 N.
The buoyancy aid should be tried on to ensure proper fit. A simulation will demonstrate to what extent the aid will ride up along the body. Excessive riding up may cover the wearer's head or prevent the swimming movements necessary to stay afloat.