Absolutely gorgeous romper Open back - adjustable straps on the back - changes bust size - elastic on back gives room for stretch on waist size Small measures bust Approx 18 inches across (adjustable with straps)waist approx 13 inches across -25 inches long Medium- bust approx 18 inches across (adjustable with straps)waist -13 1-2 inches across-25 inches long Large- bust approx 18 inches across(adjustable with straps)-waist approx 14 inches across- approx 25 inches long