The SATTVA copper bracelet is a fixed-size, non-adjustable piece of jewellery. To ensure it fits comfortably, you need to know the inner circumference of the bracelet (which should be listed in the product specifications) and compare it to the circumference of your own wrist.
To measure your wrist accurately, use a soft measuring tape or a piece of string you can later measure against a ruler. Wrap it snugly (but not tightly) around the widest part of your wrist, usually just below the wrist bone. This is your wrist circumference. For a comfortable fit with a bracelet like this, you generally want the bracelet's inner circumference to be roughly 1 to 1.5 cm larger than your wrist measurement. This allows the bracelet to slide on easily and sit loosely without being too tight or too loose and likely to slip off.
Since it's made of solid copper, the bracelet has very little flexibility or 'give'. It's best suited as a finishing detail for casual or polished styles, so a proper fit is key for it to look intentional and feel comfortable for regular wear.
If your skin is sensitive to metals, a proper fit that doesn't rub or pinch is also important. Stop use if any irritation appears.