Swim ring

A swim ring (also known as a swimming ring, swim tube, rubber ring, water donut, floatie, inner tube, or, in the United States, a lifesaver) is a toroid-shaped (hence the name "ring" or "doughnut") inflatable water toy.

The swim ring was derived from the inner tube, the inflatable inner part of older vehicle tires. The inner tube, when inflated, was used as a water toy, and as a floating object to lounge on.