I wouldn’t advise buying an iPad just to use as a secondary screen (and a touchscreen one at that) for your Mac. However, if you’ve got an Apple tablet, might as well get the extra mileage out of it.
Enter Twelve South’s HoverBar 3, an US$59.99 adjustable arm that “floats” an iPad next to an iMac or Apple display, allowing you to use the tablet for extra screen real estate. The HoverBar 3 works with the iPad (second, third and fourth generations), iPad Air (first and second generations), and iPad mini (all versions). I've tested it with an iPad Air 2 and an iPad mini 2 on a new iMac. I’m not sure if it will work with the upcoming iPad Pro.
I use a HoverBar/iPad Air set-up to keep Calendar, Messages and iChat open on the iPad, with the software I use most during the day — Pages, Safari, Mail and Pixelmator — on my iMac’s screen. You could also use the HoverBar/iPad combo to monitor a Twitter stream, stocks and local weather — or run FaceTime on your iPad while working on your Mac.
Installing the HoverBar is relatively quick, though it takes a bit of muscle and patience to tighten it sufficiently so that it doesn’t sag like RIM stock. Thankfully, Twelve South includes an allen wrench for tightening — and you WILL need it. (Also, remember this great piece of advice when it comes to tightening and loosening just about anything — leftie loosie, righty tighty.)
I can’t emphasize this enough: you have to make sure the connections are REALLY tight. If not, the HoverBar will droop under the weight of the iPad.
The HoverBar features a black, heavy-gauge, adjustable, gooseneck steel arm that measures 22 inches. You can flex and twist it to find the best position for viewing, swiping or tapping the iPad. It has a solid metal, silicone lined clamp that can be attached to any iMac or Apple display with an L-shaped stand. The vise-like clamp is designed to leave no mark or scratch on your Mac equipment. However, I found it easier to secure the HoverBar on the edge of my desk. Experiment and see what works best for you.
The HoverBar’s secure, ball-mounted display clip can be rotated horizontally or vertically and can also be tilted back and forth. Conveniently, you can use it with an Apple Smart Cover on your iPad.
Twelve South is nice enough to pack a collection of cord managing clips in the HoverBar package. This allows you to keep your iPad charged or synced with your own cable, held in place against the steel arm instead of dangling beneath it.
A must-have complement to the HoverBar is Avatron’s $14.99 Air Display 3. With Air Display, laptop, notebook and desktop computers running Mac OS X or Windows, automatically recognize a tablet as a secondary monitor, returning to single-screen mode when the app is closed. Or you can use the software to “mirror” the main monitor with the option of using the touch screen — or such functions as a calculator, painting, games or demos — or a mouse.
The HoverBar isn’t a necessity as far as Mac peripherals go. However, it’s very handy for putting the iPad to use when it would otherwise be loafing. And no one wants a lazy iPad.