Convenient to carry with your bag when you are on the go. Using it to my XPS 9550 and it works really well, with the size of 65Wh gives 19.5V 4.62A (~ 90W) to your computer. USB ports provide 5V 2.1A.
You can download both the computer and the battery pack at the same time which is a really good feature.
End connector on the cable from the battery pack is 90 * angle.
The price is the upper side, but after having had it for a while so it is easily worth the thousand patches.