This device has two ⅝” pins at the end of 12″ arms. The pins swivel and rotate, and the arms themselves swing in a radius around a central hub. The “magic” part is that the entire rig is freely moving until you use hydraulic pressure to freeze it in place. Once you have what you want to mount positioned within the “3D space” of the arms and pointed where you want, the entire rig can instantly be locked in that orientation by turning the central crank. In reality they are generally used more for rigging small cameras than lighting purposes.