This is both the best and easiest way to understand the difference between V.V. and V.W.
As a final note, I personally wish to add that the Billet Box is my primary vaping tool. My ProVari is my back-up device. I am an ex-smoker turned vaper - it's not a hobby yet, it is currently strictly the business of getting me away from smoking - it's been some ten months at this point, and...
Saved this post here so I won't lose it. Some seriously great gear here, and it's not cheap either. Having links to most of this stuff is great too.