The new MacBook, MacBook Pro and MacBook Air models are equipped with a mini Display Port and you can connect an external screen via this or an adapter or projector. An external screen can be used as main working area or for expansion of your working table, or you can work in the "Screnn syncronisation" mode with a projector- so you can see always what is shown publically on a projector. You can use the Mini DisplayPort on VGA-Adapter to connect a conventional Analog monitor, Projector or LCD-Screens with VGA-port and/or -cord. Read the documents carefully or ask the manufacturer of your screen in order to ensure that you have selected the right adapter. Compatibel with MacBook, MacBook Pro and MacBook Air with Mini DisplayPort connection only.