downstem dimensions?

I bought a nice custome glass on glass zong back in october(never posted pics but will eventually) and i used it daily for about 2 months.

But one day when i was cleaning my room i set the zong on the edge of my desk just for a second, but then i went to grab a box and had it in my hand and while turning it around i knocked it off the desk.

So thankfully my new 170 doller zong didnt totally brake, just the bowland downstem. Now my problem is i wanna order a roor diffuser but i dont know the dimensions of my downstem and was wondering the best why to find out? i still have all the broken peices so if anyone has any info let me know please.


p.s. i did use the search just didnt really find anything useful.

 

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