QA1 Six-Link Rear Suspension Conversion Installed
Let me try....
A uniball is like a heim without a shank, it fits into a unthreaded socket, normally held in place with a C clip.
The heim is normally held by either male or female threads on a shank
I used them in the early stages of development in place of a upper ball joint to raise the upper control arm pivot
Like a heim, they have limited movement that limited suspension travel. Dirt track guys use them, that is were I came across them.