Best second screen for iMac 27"

[h2009]

Hello
I've recently been testing various dell screens as a second monitor. I've looked over the forums and all the second monitor threads are now very old.

Can anyone recommend a second monitor which the colours are 100% on par with the iMac.

Both of them sit side by side!

 

[Pieterr]

A monitor with the same panel (LM270WQ1) and similar looks like the iMac:

http://www.iiyama.com/gb_en/products/prolite-xb2779qs-1/