My wrist is just over 15cm. I’ve tried the cuff on several times over the years and each SA told me to go with a 17! The 18 was far too big and the 16 too snug. 17 is ideal for me as there’s movement up and down my wrist but it’s secure and doesn’t fall down my hand. Hope that helps!It looks so beautiful!! May I ask what your wrist measures please if you were advised to get a 17? Thank you