Installation (continued):
To install an external 3.5" device into an open 5.25" bay you must use the included drive rails, shown in the below left image. There is only one bay cover with the pop off 3.5" slot, and it is shown in the below right image.
The drive bay covers have a mesh finish, which will help keep dust from getting to the system's components. The mesh isn't cloth like I have seen in other covers, and it is definitely very easy to clean and easy to remove from the front panel. To my dismay, some of the tabs on three of the covers were broken off in shipping. It isn't a really big deal because I used two of the bays for 5.25" devices, but of course the only 3.5" bay cover had broken tabs. In the images below you can see the good tabs, and the broken tabs for the 3.5" cover.
The biggest design fault in the Cooler Master Cosmos S full tower case is the 4-in-3 hard drive cage. Removing it from the chassis is just too difficult. It is fit so tightly in the chassis that you will scrape the metal sides that hold the hard drive cage. It is very annoying if you ever want to install or remove a hard drive, as you will need to unplug all connections to the drives, remove the three device bay covers in front of the cage, remove the whole cage, make your drive changes, remount the cage, replace the bay covers, and finally plug all connections to the hard drives. I installed just two hard drives, and it was a long process as described above, capped off with the fact that each drive had to be screwed to the cage (nothing tool-less there).
Installing 5.25" bay devices is very easy compared to the hard drive installation. Slide the drive into an open bay, press the big blue button, and that's it. Below is a shot of the two 5.25" devices and one 3.5" devices installed.
