For the uninformed, the Nyko Data Bank replaces the default HDD cover of the PS4, enabling gamers to add compatible 3.5-inch disk drives. It also includes an LED indicator to show when the system is accessing the hard drive. If you are interested, you can preorder the upcoming accessory on Amazon.com with this page.
Sony decided to include a 500 GB HDD with all PlayStation 4 consoles. However, you can quickly run out of space as all games, including retail releases, have to be installed. This is especially true if you have some of the bigger-sized titles such as Call of Duty: Advanced Warfare, Dragon Age Inquisition and The Last of Us Remastered. Not to mention that you also have to deal with patch updates and downloadable content.
Since the system does not currently support installs via external HDDs, the only way to increase capacity is by replacing the default drive with another one containing more space. If you have an extra 3.5-inch hard disk drive lying around, then you might want to check out the Nyko Data Bank when it launches.