This item can only be used together with a Multi Mount pole. It's very flexible and easy to use.
It comes with four separate segments: L, M and two S. Each segment has a ball bearing that can be moved freely to any position. You could combine segments from two or more sets if needed.
To attach it, you first need to unscrew the knob with a 1/4 inch screw from the Multi Mount. You will need to screw that knob into the last segment of your arm. I do believe this could have been designed for easier and faster assembly.
It gives me the feeling that it was meant to be positioned once and rarely repositioned. As a teacher, I move it from one desk to another, from one camera position to another and so on.
With screws half tightened I can reposition my USB camera during lectures without touching the screws. I don't think it would work on a heavier DSLR.
Every time I want to take a segment out, I have to unscrew the bearing so much that it falls into separate pieces: two segments and two plastic holders. Somehow, this does not amuse me.
The good thing is, if you have more than one Multi Mount or a Solid Arm, that you can use some segments on each.