I prodealed a Mtn Hardware Conduit job and it totally sucks for vapour dispersion as the bottom, like most bivy sacks, is PU coated nylon. THE BEST WAY TO GO is with MEC's emperor Penguin overbag as the whole thing is Dryloft and the synthetic layer will wick most H2O out of a down bag. Mind you, it can't stand in for a tent like the Integral Designs unishelter, which I have found is actually quite useful here and there.