These amazing fidget toys use the power of magnetism in such a fun way! FinGears are rings that magnetically snap together, and can be twirled, rolled, used for games, trick shots, and so much more! They come in 3 different sizes for a variety of people to enjoy. The movement of the rings is mystifying and soothing, providing a great stress relief or therapy toy for those who struggle with anxiety and concentrating. Combine sets to create cool magnetic force games. Each set contains 3 rings. Sizes for rings are as follows: small – 16mm, medium – 19 mm, large – 21mm. Length is measurements inside the rings.