What it is
A pair of apps that turn spare Apple devices into a real second monitor for a Mac, creating a virtual display that macOS treats like any external screen. Video is hardware-encoded as H.264 or HEVC and streamed over a USB cable, Wi-Fi, Thunderbolt, or Ethernet, with tap, drag, and two-finger scroll input from touch devices. Mac owners with an idle iPad, iPhone, or older Mac can extend their desktop without accounts, subscriptions, a shared Apple ID, or a hardware dongle.