Chic and unique, this empire-waist halter prom dress is exclusively sold at PromGirl. The plunging v-neckline of this long prom dress gets support from wide halter straps. Completely backless, this tight v-neck prom dress features two thin straps that wrap horizontally around the back to create a stylish focal point just above the dramatic floor-length back sash. Sleek and sexy, this open-back halter prom dress ends with a thigh-high side slit.