Looking at the Icy Dock MB991IK-B you will notice that it is a standard 3.5” bay device that houses a 2.5” drive. On the front of the drive you can see that there is a key lock to lock the drive in place. This is just in case you keep your drive in the enclosure all of the time and want it to be secure. There is also some venting in the front to allow airflow to be brought over the drive while it’s in the cage.
On the side of the drive you can see the mounting holes used to mount it into your 3.5” bay. Along the top they have a larger venting area where the heat can escape from the top of the enclosure. On the back of the enclosure you can see where the drive is to be connected. There is also a connector for the SATA power, along with a regular SATA data connector and a connector for SAS hookup.
Next we have the hard drive cage. You just slide out the piece next to the lock towards the lock. Once you do that the cage will pop out a little bit so that you can pull it out the rest of the way. After removing the drive you will see a plain HDD cage where you can mount the HDD from the bottom of the bracket.