Since Davinci hasn't commented on this vapor seal yet: there seem to be two possibilities for this vapor seal.
1) a cap that covers the bottom grill
2) rubber band that fits around the slit (connection between bottom part and top part of the Ascent)
@ Reviewers:
Could you try to emulate this by using materials of your choice and give it a try? Maybe you could cover the grill and/or slit with a cotton pad and then cover the cotton with aluminium foil to make it air-tight. And then record a video of the vapor production.
Because for some people (personally I don't care), dense clouds seem to be important and this would give us all a quick preview on the "improvement" Davinci seems to be working on.
I don't quite get this cloud argument. This seems to be something coming mostly from people who were into joints/bongs before. I hardly touched cannabis before vaporizers were born, so to me cloud production isn't really important. But apparently dense clouds look a bit like smoke and maybe people associate smoke with getting high. Or maybe they just enjoy the visual aspect.
Cloud density/volume should be determined by the following: temperature, bowl volume, amount of material used, how air-tight the bowl is and how much clean air is mixed up with the vapor when it leaves the mouthpiece. Then it also heavily depends on the environment (lighting, temperatures) in which you're vaporizing.
In the case of the Ascent all of the above (except air-tightness) are already fixed, so with this last improvement it should produce fairly thick clouds like the Solo. Even more so, because it uses more conduction than the Solo. If it doesn't, then maybe the temperature reading isn't correct or it simply doesn't reach 420+ F. Which would be kind of sad because I don't just want to get high, I want to get stoned, too and for that you need the higher temperatures.