Light Hanger Question

Hey guys,
I got these today from ebay, but they have no directions, or self explantory way of using them.

Does anyone know how these work?

u put the hooks on it urself. one on the string one on the stop black hook. then u use the crank on the side to adjust the hieght

barely loosen the wing nut when you have the hook tied on and your hanger in position..then lightly tug down to where you want...then tighten the wing nut again when you are at the desired height.

Thanks guys for the help, got the light made, and the hangers figured out today!!!!