Update
The divider is still for sale, I just pulled it from the truck and secured it in the garage.
In general, I believe the divider is more usful than the extender. I ordered it with the truck. When the truck came in, it had both, so I paid for both. Recently, I had an ARE LSII hard tonneau added. This is secured to the unitrack by four clamps, two toward the front and two toward the rear.
Obviously the clamps interfere with sliding things along the unitrack.
I could still use both accessories, but the divider could not slide all the way forward because of the front ARE clamps. Toward the rear, the sliding bed expender just essentially become a nonsliding extender, that I can rotate in the two positions or just remove.
Because of above, the divider has limited value to me because I don't want to lose the front say six inches of the bed.
Anyway, probably more than you wanted to know about these two accessories!