Hey this is handy.
An app for lucky Mac owners that lets you use your iPad or iPhone as an external screen.
Duet’s software gives you a Retina display at a smooth 60 frames per second.
There’s no lag at all, but you must connect to your Mac with the 30-pin lightning cable.
To all intents and purposes, it behaves exactly like an external screen is supposed to, albeit a smaller version.
It works with all Macs 10.9+, iPads, and iPhone iOS6+.
Read more at idownloadblog.