Luxury Mermaid High Collar Sweetheart Illusion Sequin Rhinestones Hunter Green Formal Dresses Sheath Sweetheart Keyhole Long Formal Dress Hunter Green Formal Gowns & Windsor Michelle Hunter Green Sheath Off the Shoulder Sequins Long Prom Dress. This Sheath Sweetheart Keyhole Long Formal Dress is perfect for any formal occasion. With its flattering silhouette and beautiful keyhole detail, this dress is both elegant and sophisticated. Made from high quality materials, it provides a comfortable fit for a confident and memorable evening.