Twelve South BackPack for iMac and Apple Displays | Hidden Storage Shelf for Hard Drives and Accessories (silver) Helps create an organized workspace by elevating hard drives and other peripherals off your desk Adds a space-saving shelf that mounts to the back or front of your iMac or Apple Display Holds up to 3.5 pounds of hard drives, peripherals  even a MacBook Integrated cable rails allow for handy cord and cable management with integrated vertical pegs to supported hard drives Compatible with iMac (21 and 27-inch models), iMac Pro, Apple Thunderbolt Display and Apple Cinema Display (21 and 27-inch)