What do you need?
To measure the size of your wrist you need:
As you can see on the image, you should measure your wrist just below the wrist bone, where you would place your wrist watch.
Wrap the piece of string or measuring tape around your wrist and mark where it meets to get your approximate wrist measurement.
Put the piece of string along the ruler and pull it tight.
Measure the length from the end of the string to the mark (in centimeters or inches). Select the nearest size from the drop down menu on the product detail page.