My understanding is that the Wetbox is best used with a regular 510 cartomizer and not a LR cart. Even though they are supposedly modified now to work with a LR cart, there are a number of posts that mention disclaimers along the lines of "try at your own risk". I am very used to, and comfortable with, regular 3.7v vaping, so when I bought my Wetbox, I went with regular 510 cartomizers as recommended.
Some people have posted that the Wetbox is prone to switch failure. There are many theories why. One is that people using atomizers rather than cartomizers end up leaking juice all over the switch inside the unit, causing it to eventually short out. Another is that the LR carts are the problem. One post said that the majority of the problems were not with the 510 version, but rather the 808. So, again to be safe, I went with a 510 version with regular 510 carts and the high drain 14500 battery. And a few prayers to the "reliability gods".
As for batteries, Drew at Nhaler (where I bought my Wetbox) only sells the LiMn High Drain 14500 3.7V 600mah Battery for use with the Wetbox. He includes one with the device. It's an unprotected battery, but he told me that the battery uses what he referred to as "safe chemistry" that prevents it from exploding.
Another post somewhere on this forum also says that these batteries are safe because they are designed to handle the higher drain of a LR atty. I am assuming (and we all know what that means) that the high drain battery used with a regular 510 cart should be well able to handle the drain with no chance of overheating or whatever causes some batteries to explode.
Today's the first day with my Wetbox. So far so good. As for the vaping experience with it, I could not be more pleased. It does exactly what I wanted it to do: Provides a good throat hit, lots of vapor, and virtually eliminated the need to carry around a bunch of "stuff". Of course, until I gain total confidence in this mod, I'll still carry an extra, charged RN4081 with a fresh cart with me as a backup.
To anyone considering this mod, all I can say is that it's a good value at around $50, and if it lasts only a month, it's still cheaper than the 2 cartons I would have gone through in that time. At nearly $100 a carton where I live, $50 is a steal.