Above is a truehybrid.
There is no 510 connection.
This one is a nemesis mod and 3d rda.
The 3d is m20x0.5 threaded in order to thread directly onto the m20x0.5 threads of the nemesis tubes. The 3d I have also came with an m20x0.5 to 510 adapter so that it can be used of standard 510 threaded devices.
The 3d is rather finicky to work with, and recently I have discovered that it somehow manages to leak/seepslowly out the bottom from somewhere at the centerpin apparently.
The fakebrids are the mods that come with a 510 thread with no centerpin.
The name 'hybrid' is actually a poor description of what is really going on.
Another example of a truehybrid rda is the elm, which is threaded for ... I believe... m20x1 threaded tubes.
The vapelyfe is another one, but I don't know the thread.
I have not found an m21x1 threaded rda.