The swim ring was derived from the , the inner, enclosed, inflatable part of older vehicle . The inner tube, when inflated, was used as a water toy, and as a floating object to lounge on.
The swim ring is not designed to save individuals from drowning.
A swim ring consists of two identically-sized layers of flat , one of which contains a . The shape of each layer is like a large with a smaller, circle removed. The two layers are joined at their inner and outer edges, sealing an air chamber inside.