I've contacted Wotofo directly about their provided glass with these RTAs. I can not complain one bit about flavor or cloud production of these RTAs, but I have never broken a single glass tank I've owned in the many years I've vaped, however of the 3 I purchased at a local retailer (Blue, Black w/ Red Drip Tip, and Gun Metal Gray) I have had a 6 mil glass with a rubber shock ring around it break falling off my desk and landing on the carpet mod first, a second 6 mil glass break overnight waking to a puddle of oil on my dresser across the room, and a 4 mil glass break as I was showing someone the deck as I was unscrewing the bottom. I'm not a novice when it comes to builds or making my own coils so I am rather familiar with RTAs, RDAs and standard tanks like cleito's, cloud beast's and baby beast's (my chosen tanks before these three), and after providing pictures and codes to wotofo to show authenticity and weak glass, it's been over a week and I've heard nothing back from them. So now I will go public with my experience instead of keeping it just to myself and not cautioning people from buying these. If I had not bought three, I wouldn't have had enough glass to use it now. You also can not purchase glass for these as on right now so you are only limited to what comes with it, and that so far is crap.