The On The Rocks Cosmopolitan Effen is a pre-mixed cocktail made with Effen vodka, triple sec, cranberry juice, and lime juice. It is a refreshing and easy-to-make cocktail that is perfect for any occasion. The Effen vodka gives the cocktail a smooth and clean finish, while the triple sec adds a hint of sweetness. The cranberry juice and lime juice provide a tart and tangy flavor that is balanced out by the sweetness of the triple sec. The On The Rocks Cosmopolitan Effen is a great way to enjoy a classic cocktail without having to mix it yourself.