All rings are open on the back and adjustable. Size range is from 4 to 8. Please state ring size for a wider band and I will adjust to size before shipping. For bracelets loosely wrap a string around wrist and measure complete circumference. I will subtract 1.25 inches from that for the back opening to see if it will fit you. I will let you know before filling order. All stones are one-of-a-kind and cannot be duplicated.