Inner circumference: Approximately 15.5cm, with some margin of error. * If you wish to change the size (up to 17cm free of charge), please let me know after purchase. Larimar: 8mm x 2 Crystal: 6mm Crystal: 5mm Mother of Pearl: 6mm Aquamarine: 4.5mm Aquamarine: 6mm Button-cut crystal Aquamarine: 8mm Double strand of Ope-ron rubber * The knots in the rubber are not fixed with adhesive. If they come loose, gently pull them back in from the opposite side of the stone. The stones may have small scratches, inclusions, color variations, dents, and natural cracks. This is handmade by an amateur, so please refrain from purchasing if you are looking for perfection. 81