What is the best quality one out there? My BFF got one for xmas that her husband bought from Preferred vaper but it is like loose. She uses it in 18650 mode and she said the top cap pops out if she tries to screw it all together reasonably tight. I mean it feels wobbly when I hold it because she has to keep it so loose. Is there a better clone out there? I am thinking about getting her one for her b day if there is because this one is junk it seems unless I can mod it for her somehow. I haven't had time to really take it apart and look at it yet but something just isn't right. I thought maybe this was a common problem with it and someone may know of a fix. Thanks 