The length around the Adult sized silicone wristband is 8", or 202mm. This length measures the circumference of the wristband, which is the length around the perimeter of a circle:

Our Adult size wristband is the most universal size option and is most often chosen by our customers. It provides the most flexibility as it can be worn by the widest range of wrist sizes. If you're ordering for a group with a variety of wrist sizes and don't want to spend the extra fee for adding additional sizes, we'd recommend choosing Adult.