Blue Prom Strapless Peplum Evening Long Formal Mermaid Dress Strapless Blue Formal Dresses & Windsor Mermaid Trumpet Elegant Engagement Formal Evening Dress Strapless Blue Prom Strapless Peplum Evening Long Formal Mermaid Dress Aeth Royal Blue Strapless Lace Mermaid Long Prom Dresses With Slit. This elegant strapless dress features a trumpet mermaid silhouette and a flattering side slit, making it the perfect choice for formal. The strapless design allows for a sleek and sophisticated look, while the slit adds a touch of glamour. Look and feel like a modern day princess in this stunning dress.