Slap bracelet

A slap bracelet (or snap bracelet) is a bracelet consisting of layered, flexible stainless steel bistable spring bands sealed within a fabric, silicone, or plastic cover.

The slap bracelet was invented by Wisconsin teacher Stuart Anders and sold under the brand name "Slap Wrap". The slap bracelet was a popular fad among children, pre-teens, and teenagers in the late 1980s, and was available in a wide variety of patterns and colors. The bracelet was banned in several schools following reports of injuries from worn or modified bracelets.

...
Wikipedia