This bracelet is made with genuine Hokutolite sourced from Taiwan, and is meticulously crafted one by one by a professional artisan certified with the highest level of skills in precious metal jewelry making. Taiwanese High Purity Hokutolite Bracelet Negative Ions, Natural Radium Inner Diameter: Approximately 5.4cm Stone Diameter: Approximately 10mm Radium Level: Approximately 0.2μSv/h (Measurement without a window) Since α waves are not measured without a window, the actual value including α waves will be higher. This measurement without a window is just right. Also, if the measurement without a window is abnormally high, it indicates a high possibility of a fake, with high levels of β and γ, which are harmful to the human body, so please be careful. Our Hokutolite is from before mining was prohibited, and is available for sale while supplies last. Genuine Hokutolite is extremely valuable and is said to be beneficial for health, such as cancer prevention.