PLEASE HELP --- PCI E 6+2 pin connector compatability?

Sup guys

The HD3870x2 requires a 6 pin pci e and a 8 pin cable.

So in search of a psu supporting an 8 pin pci connector I came across this

http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005

It says it has two 6+2 pin pci -e connectors.

Does this mean it will fit in both 6 pin and 8 pin sockets?
Is it merely a 6 pin cable with a extra two on the side in case you need em? Or is it a solid 8 pin which wont fit in a 6 pin socket.

so does that mean, you can use the 6 pin, and not worry about the 2 pin next to it? Just leaving it there and not to worry about it? Because the graphic card that I am looking at, only needs a 6 pin, but I am getting a 700W powersuppy, and it has the 6+2