Our sports bra is made from 90% organic USA grown cotton and 10% spandex sourced from recycled PET. The straps are made out of 3/4 inch cotton/rubber elastic and cross in the back. We double the fabric in the bra in the front for maximum support for running or stretching. Sizing for the sports bra is snug to keep everything in place while exercising. You should size up if you want a more lounge crop top fit!