I had a male domeless, 18mm. The thing was beefy but when I tried on my father's cheaper "Chinese" glass it seemed to crack both of the joints on the piece. I was thinking maybe from the heat retention meeting water that was possibly left from filling, but not 100% positive. Needless to say I never tried on my pieces. I got rid of that nail, my friend was adamant to buy it, and he has not had any problems with it. He actually loves it, however I told him to constantly remove after dabbing just in case. I would like to purchase an INFINTi nail or something similar but am scared to bust my good pieces. Any ideas/tips?