Out of pure curiosity, I started wondering this today. For their size the Vapor 4 Life "short" batteries are pretty small. And for their size they preform pretty well. I can't decide if I like my new Boge Carts or the Vapor 4 Life ones better, they both make nice thick smoke when you use a high VG e-liquid. (thank you to all of you who told me to try cartomizers, by time suffering with tanks is over! Being small is nice, it means shorter battery life, but when one is out and about being lightweight becomes a big asset. So just for kicks what is the smalest model out there (small meaning short and also small meaning small in total volume.) Are there any people making "mods" to see how small things can get? What about a box-mod the size of a lighter.