Duet Display turns any iPad (or iPhone) into a lag-free second, third, or even fourth display for Windows PCs and Mac computers. It's a bit pricey, but it's also well worth the cost. I may be a journalist, but my desk looks like it belongs to a stock trader. My 27-inch iMac has two external Dell monitors, one 19 inches and one 24 inches. And thanks to the Duet Display app, I sometimes add a fourth screen: my 12.9-inch iPad Pro. Duet Display is a $16 iOS app that turns any iPhone or iPad into an external monitor for Windows or Mac computers, and it works in both extended desktop and mirror modes. Here are five good reasons why the app is worth the slightly steep price. SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe 1. iPad Pro is big and beautiful Apple’s iPad Pro is the best possible, portable external monitor. The sizable Retina screen gives you plenty of real estate to view documents, websites or anything else. 2. Duet Display (mostly) doesn’t lag Duet Display connects your iPad to your computer via an app for Mac or Windows, using a Lightning or 30-pin USB cable. Duet Display connects via a wire, so there’s isn’t much lag. I did notice a bit of lag time when I clicked around through folders in the Mac OS X Finder. It was a little annoying, but overall the value it provides is worth the minor headaches. 3. Duet Display makes you more productive If you frequently work on the road and own an iPad Air or Pro, you should seriously consider Duet Display. The ability to use two screens (say, an iPad and a laptop) in a hotel room, conference area or other venue makes you much more productive. If nothing else, you reduce or even eliminate the need to switch back and forth between apps, which can help you concentrate and work more efficiently. 4. Duet Display improves presos I also recommend Duet Display for salespeople, real estate agents, and anyone else who gives on-the-go presentations. You can turn the iPad Pro monitor to face your audience and mirror the display to drive your presentation, so you all see the same thing. 5. Duet Display is the perfect fourth screen As mentioned, I connect my iPad Pro to my iMac, turning it into a fourth monitor for my desk. That may sound excessive, but you’d be surprised just how easy it is to put that fourth screen to good use. To sum this all up, if you really want an iPad Pro but haven’t been able to justifying the hefty price tag ($799 and up), Duet Display could ease the decision making process because it makes the tablet even more useful. Related content opinion 3 top travel apps worth revisiting TripAdvisor, Kayak, and TripIt have been around for years. But they keep getting more powerful and more useful with new features. By James A. Martin May 09, 2017 4 mins Mobile Apps Consumer Electronics opinion Amazon Echo Dot gets more portable and better sound from Vaux A new speaker/dock called Vaux gives Echo Dot two things Amazon left out. But does that make Echo Dot and Vaux a better buy than Amazon Tap? By James A. Martin Apr 29, 2017 2 mins Amazon.com Gadgets Mobile Apps opinion Who's smartest — Alexa, Siri, Cortana, or Google Assistant? You won't be shocked to learn that Apple's Siri virtual assistant has the best sense of humor. But you might be surprised to learn which virtual assistant is the smartestu2014and which one is no. 2 with a bullet. By James A. Martin Apr 27, 2017 4 mins Gadgets Mobile Apps Artificial Intelligence opinion Does the world need a Windows smartwatch? The answer is, 'yes,' if you like the idea of a commercial-grade wearable for retail, hospitality, healthcare and manufacturing. But the track record of squeezing Windows into a small device isn't good. By James A. Martin Apr 26, 2017 4 mins Wearables Mobile Apps Consumer Electronics Podcasts Videos Resources Events SUBSCRIBE TO OUR NEWSLETTER From our editors straight to your inbox Get started by entering your email address below. Please enter a valid email address Subscribe