The Retroid Dual Screen Add-On adds a second display to a compatible Retroid Pocket handheld or third-party device. The touch screen accessory will allow users to play a unique selection of games made for dual-screen consoles such as the Nintendo DS and Nintendo 3DS.https://www.notebookcheck.net/Retroid-s-Dual-Screen-Add-On-costs-69-and-works-with-third-party-devices.1032905.0.html
I was looking at 2nd monitors til i settled on xreal glasses.