Forever 21 LBD Little Black Mini Dress Adjustable Spaghetti Straps Bodycon Stretchy Size S Buttons down the front, ribbed. Armpit to armpit starts at 13.5, not stretched out. Unfortunately, I don't have the material composition, as the care tag has been cut out, but it's very stretchy. Where the straps are now, shoulder to bottom is approximately 34.5".