Yam Display 4+

This app is great. It works just as you'd expect. Not all resolutions are equally responsive, so if you see people complaining about lag, know that tuning resolution can solve this. This lag is just a factor of the hardware limitations of the USB connection, something that will affect all apps like this in the same way.

I've also used Duet display, which is more expensive than Yam, but Yam is much better. Yam has more resolution options, moderately better performance, and support for split-screen multitasking on supported iPads, a great feature that Duet lacks.
If you don't need to use this with windows, I highly suggest Yam over Duet.

After trying both YAM and DUET, I finally paid for YAM and is really satisfied with its performance. YAM kick down DUET both in resolution and reliability at least with my 12.9’ iPad Pro, retina is supported and its price is acceptable, subtle lags when scrolling contents is no problem with as I often use external screen for reading static PDFs.

The only problem I have is when I turn on and off YAM several times, the main screen brightness would be changed to the highest level, which is a bit annoying, hope you guys could fixed it.

Anyway, thank you for providing us such a good app, it greatly improves comfort of my work flow!

I have used another display extensor for years but resisted going to their subscription. I finally went looking for other options and found YAM display. It works great, is easy and intuitive. Scales properly without an issue. I use it often when I am also RDK into a windows machine that has 2 monitors and it automatically tiles my 2 screens with the 2 monitor views. This is a great app and well worth the cost. I also got the WiFi version and that works great too. Minimal lag and no problems. If you want to use an iPad as a second monitor this is the way to do it.