Glad ya'll really like them, cuz I can't really say that. Since they are hand made, no two will likely ever be alike.
The first 2 I got would not fit my attys or carto's, so I sent them back. Got 2 more and the O-rings were too big and would not fit. John sent me smaller O-rings and they worked...sorta. On my clear tapered, there is so little glass below the O-ring to actually go "into" the atty/carto, that if you look at it sideways, it falls out. I've lost it twice in the house cuz it just falls out at the slightest of anything. Luckily, after looking all over, I found it each time. I KNOW if I were out and about, I would have just lost $15. Even with the replacement O-rings, they were not right. I went to Lowe's and got a bag of #47 O-rings and they work great.
Don't get me wrong, I really like them. I just really wish I could use them and TRUST them to still be there the next time I vape.
My cheap Delrin's work just perfectly and never come off unless I take them off.
For $15 each, should I have these issues when for a $2/3 Delrin, everything works great? I do NOT want to use these pyrex outside of my house because I can't trust them---at all. To me---this is jut not the way a $15 drip tip should be.
Then I see others who do not have these issues at all. As stated, each one is different. I've had 4 now, and all 4 just didn't cut it. John was great about everything, but I just got tired of paying to ship them back all the time. Again, that's just not how I would expect from a $15 tip.
So good luck Brutus..I really hope you are luckier than I.