A medium is the smallest that is offered, and it is just slightly too big, though not big enough to keep me from wearing it!  The fabric is a soft mesh material - very comfortable.  The pleats are slimming - I wish I could've found this after I had my babies!  It would've been perfect!  I get compliments on it.  Could be dressy or casual - easily worn with a skirt or jeans.  I purchased white and it is see through enough that I wear a tank top under it.