Moonstone bangle

A gorgeous chunky rectangle shaped silver bangle 3x2mm so nice and substantial.
The charm is 16mm diameter with a 10mm Moonstone with a detailed bezel surround.  The reverse of the charm is stamped with stars. The charm is joined by 4 small silver rings. 
These are made to order so they're may be slight differences to the Moonstone.
Please let me know a bangle size when ordering,  I can do the average S M or L or if you have an existing bangle you can measure the inside diameter of that.