Lastolite TriFlash Bracket with 3 Locking Shoe Mounts

The TriFlash puts up to three flashguns on one light stand and behind one modifier. This is the shoe-lock version, where each of the three mounts carries a screw lock rather than relying on the gun's own catch.

That matters because hotshoe feet are not made to a common tolerance, and a gun that latches fine on one bracket can rock on the next. There is also an umbrella socket in the bracket body.