a ring made of buoyant material which is thrown overboard to rescue a person who has fallen into water; the ring is specially designed to keep the person afloat until he can be recovered from the water

Lifebuoy is a brand of soap originally marketed by Lever Brothers in England beginning in 1895. Popular for over 100 years, it is still available in the United States, through specialty shops that import it through Jupiter Imports (UK) in England http://www.lifebuoy.co.uk.