Although obviously it does not do much, it actually fits a joint, and if filled with a little amount of water, it will actually percolate, making this a pretty cool party trick!
The keychain hole is 5mm, so if you wish to scale the model down because you just like the looks of it and don't want the functionality, keep that in mind.
Both keychains are actually usable, but what is the difference? with this version, you can actually use the bong without the need of a 14mm glass slider, and stick your joint directly into it. This version has a 2.5mm inline which is small enough to let the filter in and block airflow (if you roll fatties you might have to scale it up a bit). The main problem with that is that during use the water could travel back up the inline shaft and wet the filter: THAT DOES NOT HAPPEN!! I specifically designed the inline with this problem in mind, and the result is a water-less inline with a fully functional mini bong!
PLEASE NOTE
This model is quite intricate: the columns supporting the percolator are really tiny, but even if they don't resist during printing the outcome should be functional and look the same.
Smoking is really hazardous. Especially from unsafe plastics. That is why I highly recommend you to print this in PETG if you ever think about using it even once, as bacteria has a harder time sticking to it and usually filament brands provide waterproof PETG, which makes it harder for the bad stuff to stick in.