Long Dress With Open Back Dresses BlackMax Mara Sportmax open back long dress, made of polyester based technical fabric with a percentage of elastane, features a sleeveless construction and an elongated silhouette. The structure includes a round neckline at the front and a back opening that leaves the back uncovered. The skirt features a pleated fabrication that lends depth and movement to the garment line. Suitable for occasions that require clean construction and performance materials.