Sturdy Girl Sports Las Vegas Bra Body: COOLMAX 79% Polyester/21% Lycra, 4-way stretch, yarn wicking. Our bras run somewhat small. Do not order a size down. If you are in-between sizes, we suggest you order a size up in our bras. Patented Sturdy Support System (S3) uses (1) compression, (2) encapsulation, (3) suspension, that supports each breast within the M & W overlap frame. A wide rib band and cushioned shoulder straps add superior comfort. Honeycomb padded liner that bans the "headlights" and wicks sweat away practically before you even feel it! Cute keyhole back design catches attention and keeps you cooler. Designed for high impact athletic endeavors, but comfy enough for any activity.