Great causal tank! the back is a bitter longer than the front - i'm 5'6" and the back-model shot was right on for where it his me at the hip/butt. the material is a poly/spandex/rayon mix that feels predominately like polyester and rayon and has a little bit of give.

 i go between a medium and small in most retailer tanks and like to achieve a look that is somewhere in between form-fitting and flowy (quick stats - 130 lbs, 34c) and the small was perfect without being too tight across the chest.