Wasn't sure where to post this but I brought out my Duet app (which I believe is 1/2 price right now) which I've owned for a year plus--have not used it because I discovered the Astropad app works better for original purpose, but a friend reminded me of the app--and I dragged it out again. If you have a MacBook and an iPad or iPhone for that matter (though how effective it would be on the phone because of screen size, not sure), you can extend the geography of your MacBook Pro screen (or actually a Mac, PC, etc) which is very useful once you open 2 or more windows or apps. Its easily set up--a USB to Lightning or TB cable to connect iPad to MacBook, installation of Duet on iPad and Mac and you are good to go. The iPad, when arrangement is set up in Duet settings, acts as an extension of the Mac screen and you can in real time slide apps, Safari tabs, other windows over to the iPad giving you a lot more room on your screen. The touchpad (or mouse in my case) works on both screens, it just acts as part of your Mac screen--period. I tried enabling the Touchbar as the new MacBook Pro has, and its also useful in some apps. It takes only a selection in the Duet app--so for those that covet the Touchbar, here's a very inexpensive way to acquire it for your older MacBooks. All in all this is a really useful app if you have both devices. I'm using it with the 12.9 iPad Pro but from Mini to the big Pro would be great. They also have a subscription for additional options using Pencil, etc for graphics (I'm assuming-I use Astropad for those purposes).