This is the authentic Lumberg Jack.
It's just feels good to hold and work with. It feels German in it's exactness and practical simplicity. The plastic is sturdy. You should really try these. I think you'll like them.
There are differences from the clone. The metal is thicker than that of the clone, and the solder lugs are different.
It is Lumberg part number: KLBM 3. Check out the data sheet for more info.
Folks love these for 1590A and 1590G builds, as Lumbergs are much smaller than a Neutrik jack.