By connecting one to a macbook pro, as one example, you could utilise up to three displays: one built-in, one via the existing dvi/hdmi/displayport, and one more via usb.
Hooking up two monitors to my macbook pro
Apple has implemented quite a few different port types over the years, and your imac or macbook it might feature any of the following:Mini displayport was announced by apple towards the end of 2008.
How to hook up two monitors to my macbook pro
Up multiple monitors onto your MacBook Pro, MacBook Air, or even iMac is very simple and easy.
It looks like this:Unfortunately, if you were hoping to plug your new macbook pro into a second display you may be out of luck as the macs that use thunderbolt 3 or usb-c wont work with any of the following adapters, even if you use a thunderbolt 3 (usb-c) to thunderbolt 2 adapter.
Prior to macos sierra it was possible to use a third-party mini displayport to dvi adapter with a mac, but since sierra launched mac users who were reliant on that set up have found their monitors have stopped working with their mac.
Old crt (cathode ray tube) monitors were vga but there are flat displays that use vga - they just convert the vga connector's analog signal back to digital.
For example, you might have an external display to the left of your macbook in your workspace.