Chiara Boni La Petite Robe Seki One-Shoulder Gown. Size 16. 
ONLY AT SAKS. Cut in a dramatic silhouette, this asymmetric gown has a single knotted shoulder strap and ruching at the hip to highlight the curve of your waist.
One-shoulder neckline
Sleeveless
Ruched hip with drape
Polyamide/elastane
Hand wash
Made in Italy
SIZE & FIT
Trumpet silhouette
About 64" from shoulder to hem
Model measurements: 5'10" tall, 32" bust, 24" waist, 35" hips
Model is wearing a US size 16