The Medium Sphere EcoSphere is 5.5" in diameter and contains 7 to 8 shrimp, algae, bacteria and other microorganisms, creating a completely balanced ecosystem capable of supporting and sustaining life within. This is a living item and ships via FedEx Priority Overnight with a signature required upon delivery. After you select “Checkout”, please use the Calendar to select your arrival date. FedEx will not deliver this item without a signature. EcoSpheres can only be sent to addresses in the U.S. excluding Hawaii, Alaska, Puerto Rico, P.O. Boxes, A.P.O. Boxes, and F.P.O. Boxes.