I have an iMac20.1 and would like to attach an iMac 17.1 Late 2015 or iMac 11.3 Mid 2010 as a second monitor. Which cable does this work with? I have ordered this cable https://www.galaxus.ch/de/s1/product/apple-thunderbolt-kabel-2m-andere-video-kabel-432765 which unfortunately does not fit. Do I need the above adapter or what other options do I have? Thank you very much!