One of my things is I want to keep it under 7 inches. I have a nice little pouch that I keep my pv in so it doesn't get banged up in my pocket. Just from what I have seen, the 18650s make it way to long for the pocket and to travel with. Like I said, there are a few things I am picky with. For home use, I wouldn't mind but I want something that can fit in my pocket easy enough.. I'm sure it's just wishful thinking lol