COCO Strappy One Shoulder Long Sequin Formal Dress 12009. Rows of sparkly sequins make this one shoulder long formal dress a dazzling choice for your big night. Whether you're going to prom, a military ball, or another formal event, this open back evening gown will shine in the spotlight. With rows of sequins from the asymmetrical neckline to the floor, this fancy long designer dress from Primavera gets a sexy vibe with thin bands that criss cross over the open back before lacing up for the best fit. The one shoulder gown includes a ruffled cap sleeve and a fully lined long skirt with a sheer sequin overlay that flows to the floor in a flattering a line shape that finishes the design. A striking design for the girl who loves to impress the crowd, this one shoulder long sequin formal dress is a traditional style with a modern details.