Sizing and Fit: Such a great piece to have in your wardrobe. Ideal for the car, and such a stunning colour! It comes in four sizes: the S will fit 10/12, the M a 12/14 , the L 14/16 and the XL will fit 16/18. However there is room for sizes up and down from that guide because of the way it ties. So if you’re a 20, I would try the XL, and equally, if you’re a 8, then you’ll be able to make the S work.