Yeah that might be a pseudo air kit for the F3, a "workaround" so to speak. I just remember it was not possible for an air kit because of the upper slide on the 3CB and 602CB stove. For what its worth, don't think any secondary air is adjustable, in closing the primary air down, you induce the stove to pull more air through the secondary air system due to draft still wanting to pull air into the stove.