If you have a desired inner circumference, please be sure to let us know before purchasing. It will cost an additional 50 yen for every 1 cm increase. Reducing the size is free. Inner circumference: Approximately 17 cm (stretches) Crystal 8mm & 10mm Matte Onyx 8mm Rondel *The number of stones will vary depending on the size. 【Crystal】 Crystal is a versatile stone. It is the basic of all power stones. As can be seen from its use in purifying power stones, it has a very strong purifying effect. It can absorb and purify negative energy for not only power stones but also everything else, bringing it to a pure state. Placing crystals as interior decoration in a room will also purify the space. It is especially effective when placed in places with heavy foot traffic, such as the entrance. Of course, it also has healing power for the mind and body. It affects the mental aspect, but especially affects the human immune system, repelling negative energy from the outside and maintaining a healthy state. In addition, it has the function of activating vitality, so you can obtain vibrant health and beauty. *Because they are natural stones, the color and pattern may differ even for the same stone. *Colors may appear different from the actual product depending on the lighting. In addition, natural materials may have cracks and inclusions. Please understand this beforehand.