Chico's Black Label Tunic Top

This is a Chico's size 00, which in 'regular' misses' size is a XS. This would be way too large on a XS. The armpit---> armpit is 20.5 inches. So I listed it as a Medium to ensure appropriate sizing. This is from Chico's "Black Label" collection-it's their high-end class of clothes. High/low tunic with solid black front, animal print back. The front has some stretch to it(95% rayon, 5% elastine); back is 100% polyester.