You should talk to Oregon Glass Blower, he can do custom 18 mm male stems, can even cut down the joint to make sure they fit the tetra!
I shared these in the tinymight thread, but make sense to share here since it is clear scientific glass that works with a very many vapes!
My new Oregon Glass Blower customs arrived today! They are perfect, the special mouthpiece of the 18 mm J-Hook is so much better (modeled after the Lamart mini j hook mp) and it is even a little more compact than the 14mm one (which is now going into storage until I can find someone to cut off its flared mp lol) Meanwhile the new custom prototype spiky bent 18mm female mouthpiece also renders the whip adapter less useful as a mouthpiece now. The cooler could probably be made even longer too, though as is the cost is $45 each if anyone is interested... Time to test them out, will report back, but just looking at them I already feel like they're going to be my go-to pieces at home, where I always am now!
OGB can work with you to make a custom if you email him, but he also has a lot of great pieces ready to ship in the shop too (I think coolers like this may be added soon enough
)
Actually kind of wish I could have gotten some color in here, but practicality is more important than superficial beauty of course!