Celebrate in glamorous style in this long prom dress that combines sleek design with bold details for a fabulous look. The floor-length formal dress features a sweetheart bodice with shoulder straps that lead to the one-of-a-kind caged-open-back detail with daring cut outs. In curve-skimming jersey fabric, this slinky evening dress showcases the silhouette before opening in a flirty side slit. A trendy exposed zipper adds shimmer to this long sweetheart prom dress, under $150, that is also appropriate for a winter formal or a military ball.