I bought this for my daughter and ordered the size she normally wears. It fit bandwise -- but the cups stuck out on top.  It hooks on the front bottom with one clasp -- the rest of the front closure should go straight up, it doesn't it leans forward.  You could never wear this under a t-shirt.  It's gone in the Goodwill pile.  It fit perfectly, if not for that feature.  And the front close feature was what she was looking for.