It's basically a frame brace for your X axis. It works really good with this frame braces: http://www.thingiverse.com/thing:1872162.
It's hollow and you can put all of your cables through, but you will need to use another wire to pull the last few connectors through.
If you like it, I can make it even better - It's kind of hard to get it in the frame itself.
So first you put both struts together with the washer 2 and put the washers 1.2 on, and screw them to the inner end of the thread. Later put in all the cables except the ones from the hot bed. Put the strut in the frame, tighten the inner washers and put on the outer ones and tighten them. Then pull the last remaining wires through and you're good to go.
Oh, and If you like it, please tell, since I'm planing to remix these supports, so you can tighten them on the other too:
Maybe I will even make the same thing for the bottom of the printer.
Oh yeah, and one more thing, after you tighten the middle connecting washer, don't try to get it back apart, or you will crack the struts