Here is what Seagate tells you about one -
http://www.seagate.com/www/en-us/products/external/expansion/expansion_desktop

In essence it is quite simply additional storage accessed through its USB interface. It is designed to simply save documents or other dat directly to it or by "dragging and dropping" from any other storage media your computer can access.

It does NOT come with any "automatic backup" software so if you want any automatic backup you will need to get a third party solution and Acronis True Image would be one solution to look at.