Theory Bustier Top in Black. - size XS (also in M, S) Theory Bustier Top in Black. - size XS (also in M, S) 100% triacetate. Made in China. Dry clean only. Smocked bodice. Lightweight twill fabric. THEO-WS917. L0209521. 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.