Salutations FalcOpus, Interesting question as i gave it a quick 30 seconds visual sweep and among the very few with no external parts that will risk to fall and end up being lost i could only imagine the Vaporfection miVape and iOLite Wispr as possible candidates, although i can't even tell you what's inside any of them exactly... My HerbalAire was a precious tool but i can't see myself trying to assemble a bag in complete darkness, actually i recall always searching for my glasses to put them on; not to mention its teflon opening can get quite a bit hot after a while, though i suppose that's not insumountable if training supervision is available. Well, at least the HA v2.2 has a rotary button and it's not too difficult to manage, for people with eye sight... But does it provide audible feedback? I don't think so and yet i don't know for sure as i had the v2.1 older version, actually. In any case, after looking at 210+ of them i'd say it's far from being an easy challenge!!