By the way, I just want to say again how pleased I am with my Hcigar VT75. I got it just because it was cheap, and as a backup to my eventual purchase of a Therion 133. The VT75 in no way deserves to be just a backup device, and I dare say I'll have to decide which to carry with me each morning, the Therion or the VT75.
It's solid, looks much better in person than in pictures (in my opinion), it pockets well, and it vapes like a dream. I get almost a full day on one 18650 keeping my coil at 470f, and I vape roughly 15ml a day.
The only issue, as others have mentioned, is the threading on the battery cap. The threads are thin, and there's not much purchase for your fingers on the cap. It's hard to get is started, but once you do the threads are smooth as butter. The trick I've learned is just to slowly turn the cap counterclockwise until you feel it sort of "click" into the topmost thread. A clockwise turn from there starts it every time and it goes on easy.