Theory Square Neck Rib Dress in Ivory. - size S (also in XS) Theory Square Neck Rib Dress in Ivory. - size S (also in XS) Self 1: 69% rayon 29% nylon 2% spandexSelf 2 & Lining: 100% poly. Dry clean only. Partially lined. Pull-on styling. Ribbed bodice. Pleated detail. Imported. THEO-WD400. K0105611. Theory is a visionary concept for modern intelligent fashion forward people. Founded in New York and made by the finest of fabrics, this makes the working everyday person feel powerful, ready to face their day.