We have our outer membrane, and this entire structure is our prokaryotic Flagellum. So we essentially inside the inner membrane, we have two proton rings. Attached to that, we have a shaft or rod. Then we have this sleeve structure. We have the hook, and finally, this entire portion, which basically extends this way, our Flagellum. Now, the Flagellum, this portion is the rigid hollow cylinder that is composed of the protein Flagellum.