NO061222601 2-piece set! Terahertz Vibrates 1 trillion times per second Approximately 10.1-10.6mm Inner circumference approximately 16.1cm The vibrations promote blood flow, relieving stiffness, etc. It's a stone that's attracting attention for its effects on beauty and health. According to NASA, terahertz waves are "transmission wavelengths" that penetrate matter, reaching human cells and having an activating effect. It's a stone currently being researched worldwide. For maintaining health, promoting beauty, extending lifespan, and eliminating cancer cells. Also, it can enhance your own inherent abilities. Recommended for those who can't shake off fatigue, those who can't get rid of ailments or pain, and those who want to live with a positive attitude. It's a very light stone, so it's comfortable to wear. The source of action and thought is physical and mental health. Effective for stiff shoulders and sensitivity to cold.