Free Color calibration device: Pantone ColorVision.
I got this a long time ago. Its software runs on Windows only. (I have since switched to Macs.) It's an old version which is not supported by ColorVision any more. I have upgraded to a newer model.
Here's an eBay link to what looks like the same thing I am offering: https://www.ebay.com/itm/Pantone-ColorVision-ColorPlus-Monitor-Calibrati...
Includes colorimeter, CD-ROM with software, and install instructions. No box.
So, if you use Windows and want to try it out, call me to claim and arrange pickup.
Rob Craighurst
(434) 760-0525