I recently bought a TFV12 and it comes with the v12-t12 already installed in it. I could not wait for this thing to show up in the mail opened it right away and placed it on my IPV5. Well it turns out the IPV5 wont run that as it needs a .12 ohm mod and mine is a .15ohm So I had to put in the v12-q4 it works great but I realize I need more batteries. So now I am ordering the smoktech gx350 as my buddy has one and the 4 batteries seemed to last in it. The only problem we found was the gx350 wouldn't turn on found out it was the plastic separator in the battery compartment took it out now it works fine. I guess what I am trying to put out there is I hope people do there research before buying things all I wanted was a tank now I am ending up with the whole deal doesn't bother me just wish I would have ordered all at the same time rather than wait longer.