What is this HDD hard drive disk duplicator and Dock?

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So, yesterday I got an advertisement from Micro center with this new gadget called HDD cruiser mini hard disk drive duplicator and Dock. I am curious what it suppose do if I have a internal hard drive, which I want to save media files, like mp3 and DVD files to it to expand the storage space from my laptop. Would this duplicator and dock serve this solely purpose? Any computer geek know about this new device? Please give me some advice.