With a 4TB internal hard drive (HDD), you can expand the internal storage of your PC or NAS. This comes in handy when you edit a lot of videos and store them too. You can use a 4TB HDD to save more than 100 4K movies of 2 hours each, 440 music albums, or 400,000 photos. This is ideal if you work with large files or simply have many files you want to save.