While our cuffs are standard, wrist sizes aren't.
It depends on the shape of the forearm around the wrist and the bones - whether the wearer is small or large boned.
Our lace in Perspex cuffs are rigid and usually fit snuggly above the wrist but should allow movement.
The acid test is always 'does it feel right'?
If you feel it will fall off any moment then it is too lose, if you have to force it on then it is too small.
Have a look at the quick video of how to put the cuff on too.
You would be surprised how ofter we find people try to put it over their hand.