Ran into this before... :- )
On the link that was given above..
Kanger Kbox Mini 50W Variable Wattage Box Mod VV VW Mod
kbox mini (just the batt box) in the Q&A it says
"
Question::
This is upgraded version with new spring loaded 510 pin? Or its old version with a fixed 510 pin?
Reply:
Hi,Artur!
This item is the latest version with new spring loaded 510 pin.
Thanks for your inquiry.
On the kit (although I haven't looked recently) the same question was asked and answered as in your post. So I'm guessing the kit is fixed and the solo kbox mini is spring loaded. Whether the kit is Kanger and the kbox mini is a clone - not sure other than what both Wayne and Phil has said - directly from Kanger.