A fidget spinner is a toy that consists of a ball-bearing in the center of a multi-lobed flat structure made from metal or plastic designed to spin along its axis with little effort. Fidget spinners became popular toys in April 2017, although similar devices had already been invented as early as 1993. The popularity of the toy among children and teenagers has led some schools to ban use of the spinners in class for being a distraction, while other schools have allowed the toy to be used discreetly. The toy has been advertised as helping people who have trouble with focusing or fidgeting by relieving nervous energy or psychological stress. There are claims that a fidget spinner can be used to help calm people down who suffer from anxiety and other neurological disorders like ADHD and Autism. However, as of May 2017, there is no scientific evidence that they are effective as a treatment for autism or ADHD.