Located in the Upper East Side, Flex Mussels specializes in seafood delicacies such as oysters, lobster rolls, and bouillabaisse. With a vibrant and cozy atmosphere, the restaurant offers both indoor and outdoor seating. Perfect for brunch or dinner, they also serve delightful desserts and wine. Reservations are recommended due to its popularity. Find Flex Mussels at 1431 3rd Ave, New York.