Looking a little closer you will find the three drive bays followed by room to mount eight HDDs. The clips on the drive bays are labeled with the NZXT logo and seem like they should slide forward and back like most, however, that's not quite how these ones work. A careful squeeze at the notched position releases the mounts. Two prongs are revealed that should sufficiently hold your optical drive or water bay solidly in place. Getting them to pop open is the difficult part. Even with my small hands the top two are pretty difficult to maneuver and being made of plastic they seem to be a little on the flimsy side. When I popped the top one open, I already shed some plastic. It still works but doesn't really lock down anymore unless there is something in the bay. Just my words of advice, be careful!