Thanks Tobin, I don't know WHAT he was looking at. It does beg the question that if he dives doubles, why was he confused about the H-Valve being listed.
OK. Let me clarify. One H-valve is reguired if you want to split your doubles into a single tank rig, at any point. Two standalone valves, one manifold with isolator, and one H-valve. If you don't ever split them, then you obvioiusly would not need an h-valve.
My memory isn't want it used to be, but I am fairly certain that I had a set of doubles on my back last weekend. You need to be a little more judicious about your comments. I will assure that if you make those type of comments outside of cyberspace too, you will eventually have a very unpleasant interacation with someone.