Much time has been spent Googling but I have not been able to find an answer.
What is the difference between the Kryos XT and HF? Given the different metals used, is it purely cosmetic or is there a slight difference in performance?
The HF variant has a larger distance between the threads so you can use bigger connectors. If you take a closer look at both blocks you will notice that the outer side of the HF variant is slightly extended.