Some feedback from the makers regarding the video
As for the aluminium sleeve water mark it is the "clear anodized" which would prevent the aluminium from oxidizing which would expand the aluminium itself or "aluminium rusting" caused by the ingredients in our juices which we observed when we first used apexi years back.
As for the airflow control it has two.
One is the "coil flow" which the drag would vary with your build. The closer to the ceramic the tighter but more flavor. If you elevate it, it would become a little bit less drag.
The other airflow is by using the reverse thread of the sleeve. By leaving a small gap from the base and the sleeve (ranges from 1.5mm-2.5mm) and using the top cap to lock the sleeve into place to loosen the drag.