Thanks to the cutout, the ring and the rigid bracelet can be compressed or uncompressed by physical impact, thereby adjusting the size in the range of +- 2.5 sizes depending on the jewelry. This makes it possible to wear the same ring on different fingers, and the bracelet will remain the same size regardless of changes in the season or weight. Flexible bracelets also have an extension that gives the same properties. Translated with DeepL.com (free version)