Hi Alli, I am holding this tank right now, so I can describe it to you. The built-in bra is the same fabric as the straps (which is a slightly contrasted color to the main body, but the same fabric). So the bra is the same fabric as the tank, and is very light and stretchy. The bottom of the shelf has a soft, brushed surface elastic, about 1 inch wide, with a scalloped bottom edge. I find this tank to fit very snugly, so I have it in size medium, when I usually get size small in the short prAna tanks.