New version Single rod clamp w/ Four 1/4" thread.
Single Rod Clamp for 15mm rod on DSLR Rig。
You can install an Articulating Arm on the female 1/4" thread, and install a monitor or a LED on the articulating arm.
http://www.youtube.com/user/TheCOOLLCD#p/u/9/IeN-wJY-hU8
Sometimes, the wing Knob would be blocked by your rig parts as follows.

So we recommend optional Freely Rotatable WingNut even if you Screw the Wingnut on.