Lifebuoy

buoy designed to be thrown to person in water, to prevent drowning

A lifebuoy is a protective device used for people who can't swim. It is made from torus, colored in orange-white color. A lifebuoy was originally created by Italian Renaissance inventor Leonardo da Vinci.

A lifebuoy on a cruise ship
A lifebelt floating on water
Leonardo da Vinci's design sketches for a safety wheel