Ideally you require 6 digit, 7 segment displays. But they haven't made it to Ebay yet. So im using QTY 2, 3 digit displays. The good thing about these, if you buy the 12 pin common cathode, is that you can directly remove the 4 digit displays on the max 7219 boards and plug these directly in. However, if like me, you need them next to each other, extension wiring is going to be required.