Transparent silicone tube, one unit. Alternative method of fixation, compared to the rubber strap. Some users prefer this to the strap. Should be inserted into the holes in the front piece combo, and locked into the ridges at the bottom.
The whole installation took me under a minute once I figured out the hole alignment, and it holds way more securely than the rubber strap ever did. I like that I can see exactly where everything sits through the tube, which makes cleanup simple.
The transparency makes it really easy to see when it's fully seated in the front piece holes. It's stiffer than I expected, but that actually makes it hold its position better than the rubber strap ever did.