Every mac with a mini displayport allows you to connect an external display or projector using an adapter you can use an external display as your main workspace or to extend your desktop or you can work in mirrored mode with a projector so you can view what your audience sees the apple mini displayport to dual link dvi adapter works best with displays that operate at dual link resolutions which are resolutions above 1920 x 1200 for displays that do not support dual link dvi resolutions