◇ Inner diameter: Free (using silicone rubber) <approx. 16cm> ◇ Blue Lace Agate (blue chalcedony) beads: approx. 7.9mm～8.5mm (20 beads) ◇ Apatite beads: approx. 8.2mm～8.3mm (3 beads) ◇ Weight: approx. 18.7g ◇ Blue Lace Agate & Apatite: This combination is a reliable ally for solving difficult problems. It is effective for improving reasoning and brainpower. It has a vibration that simplifies things, and is good when facing tricky exam questions or difficult problems. It opens up the circuits for clearly deriving answers. It also calms emotions and frees one from self-deprecation and self-denial. It is also good for people who talk too much, tend to fail due to talking too much, and are not good at organizing things. *The color of the image may appear slightly different from the actual product. Please understand. *Only one item♪ The item in the photo will be delivered.