Open-Back High-Neck Long Prom Dress: Atria 6550HRaise the style bar in this strappy open back long prom dress 6550H by Atria Couture. With a princess cut from the high scoop neckline to the knees, this elegant long formal dress flatters the figure for prom, galas, and other black tie events. Offered in misses and some plus sizes, this long evening gown has cut in shoulders and thin shoulder straps that criss cross the open back for a sexy vibe with every turn. The long mermaid skirt completes the