On the cloupor mini it was quite a few units from the first three runs but when added to their many other issues over a range of mods it was the thing that made cloupor off limits for many myself included. smok have a bad track record but not quite as bad as cloupor but it could do with some improving, answering people's mails would be a start that's the most common complaint I see smok accused of though my personal experience has been good always getting back to me within a day of sending them a mail. I love my xcube 2 it really is a fantastic bit of kit for the money it cost and I really like my tfv4 but its more of a treat myself tank then an ADV one as even though I diy my liquid damn thing would bankrupt me lol.