GUC Black dress with ruched front and back, size small

Black knit dress, ruched in front and back. Deep v neck and back. Simple and elegant. No size tag or materials list. Dress fits as small size and feels like a poly cotton knit. The ruching in front and back are not stretchy. As seen in close up pictures there is a cotton cord running the length of the ruching. Length of dress from shoulder seam to hem: 43in Armpit to armpit: 15 1/2in (without stretching) Armpit to armpit fully stretched: 18in Waist area: 14in across (fully stretched: 16in Please message for any info I may have left out.