Review on Transform Your Mac Laptop: OWC Data Doubler - Optical to SATA HD Converter Bracket Solution (OWCDDAMBS0GB) by Christina Johnson

I've been thinking about adding a second hard drive to my MacBook Pro since I installed an SSD. This way you can have a smaller/cheaper SSD for your regular boot drive and a larger HDD for things you don't use that often. I found it fairly easy to install, it looks a little intimidating when you open the bottom cover, but if you follow the instructions and are very careful with the cables, it's not a difficult process. Also a helpful tip, if you go to the Other World Computing website, there are video instructions to help you decide whether or not you can handle the installation. A few other apps for the second drive: Use the second drive to automatically create Time Machine backups in case something happens to the SSD. (I'd still back up to an external drive in case something happens to your laptop.) Use a second drive to run Boot Camp so you can use Windows when you need it without sacrificing space on your primary drive. (This is the configuration I use in my MacBook Pro) Overall this is a very reliable and well made product and I would buy a second one anytime I had a second MacBook Pro!