The Apple Micro-DVI to DVI adapter was designed specifically to fit the slim profile of Mac Book Air. Connect the adapter to the Micro-DVI port of your Mac Book Air & the DVI end of the adapter to an external DVI monitor or projector. You can use this cable in both video mirroring & extended desktop modes. Apple Micro-DVI to DVI Adaptor means that you can connect to an external VGA monitor or projector It can also be used in combination with the Apple DVI to ADC adapter to support older Apple flat panel Studio or Cinema Displays