[Bumhee] wanted a Cintiq, but didn’t want to pay the Cintiq ... modification is a Retina display from an iPad. With the right adapter, you can easily connect one of these displays to a computer ...

In the case of the 2015-vintage Wacom Cintiq Companion 2, this turns out to be the so-called Athena chip, which switches the display input between the HDMI port and internal display controller.