Simply put - the ultimate stud. Each side has 4 flat surfaces so spinning is impossible. 2 of them have drop stop edges, and 2 are without drop stop if you prefer a easy removal (no more HATE ATTACK when the stud doesn't loose after endless unscrewing). The rod is 15mm ALL the way for maximum grip in grip heads, and the rod is of course knurled for maximum grip.
For those situations where you really want safety when hanging the stud up side down, there is a go-through hole so you can screw your lamp head-screw into a safely hanging position instead of a clamping as hard as you can.
The center disc is a rigid piece of disc that your flash head firmly can rest on, and the disc have 4 sockets for hanging applications. The disc is cut in a way so you easily can see where the flat clamp surfaces are even though the surfaces are hidden by the flash socket.
The fact that the disc has flat surfaces stops it from rolling down from your table all the time is... well, not priceless but one less thing to raise that blood pressure at hectic sets.
The top has a camera plate screw (no more fiddling for coins, keys, teeth or screw drivers) and the bottom has a convenient 3/8" female thread for those situations where you need to mount it on stands/tripods or on the MultiSpigot Rack. (another thing to keep that blood pressure down - check it out!)