Vtg 80s Victor Costa Black Organza Strapless Fit and Flare Dress sz 4 fit 0 XS

Vintage 80s Victor Costa Saks Fifth Avenue Black Strapless Fit and Flare Cocktail Dress size 4 fit 0 Extra Small, small nick to organza at front lower hem area, made in USA, strapless neckline, hidden back half zip, covered placket with hidden snap fastening and large facet cut faux buttons, semi-rigid boning at fitted bodice, petticoat with fastening at inner waist and stiff tulle ruffle at hem, large structured taffeta bow at waist, stiff / lined or interfaced flare / circle skirt, tiered organza woven self, marked size 4 but vintage--please refer to measurements to ensure desired fit, estimated modern XS extra small 0, no fabric content listed, ~15-16" pit to pit, 12.75-13" across waist measured from outside, 12.5" at petticoat fastening from inside, 23" across hips outside, 21" at petticoat, 30" neckline to hem, 20.5" waist to hem