Can someone help me find a new downstem and figure out what size this is?

As far as i can understand there are 4 sizes of glass on glass right? 14mm/18mm/14.4mm/18.8mm?

Here's some pics of my broken downstem:


The piece that physically inserts into the bong is either 18 or 18.8, but the bowl that gos into the downstem is smaller like 14 or 14.4. I dont have anything except a cheap tape measure to measure with.. :c I want to get the right size but im worried about it, i havent been able to find ANYTHING. The rest of the downstem measures 5 1/2 inches not including what is shown in the pic.

Full pics of bong:


Whats really confusing the shit out of me was without looking at it, just from my description, the guy at my local glass shop said i needed a 19/15 adapter >_>

Check in the Glass House section of the forum, the experts are there x I think someone was asking for help with the same bong before he broke it a few weeks ago.. Sorry I can't be of more help x

4 sizes?? Hmm intresting.
I only smokebongs and i thought there were sizes 14-16-18-21
Now thats for the bong
The part the bowl goes into i thought was 14-16
I could be wrong but thats what ive always seen.
Where u located? I have loads of downstems im not using