After over a year of vaping and going from strictly stick batteries to X2s, iTatste VV V2 and finally a Vamo, I decided to try a carto tank. So many people use them and seem to think they are the best thing since bottled beer and sliced bread. I got a Raven tank from GV to "get my feet wet", which could be a very appropriate reason. It also seemed unique since there is no filler in the carto. I also got a funnel to make filling a little easier. It is well made, but that's the only positive I can say about it. It's a spill waiting to happen, wet feet maybe. There is no positive lock to prevent the tube from sliding up the carto and spilling the contents. This seems to be a pretty common weak point with tanks. The lack of filler is accomplished by, basically, enclosing a T3 style wick system inside an empty carto shell. The funnel does make filling easier, but the whole assembly needs to be kept tilted to let the air inside the tank out of one hole as the liquid flows in through the other hole. Then, the funnel needs to be rinsed when the tank is filled. Getting it on a device is a chore because the carto spins inside the tank making it necessary to tighten it with the tip and the tank. Taking it off is another balancing act between tip, tank and friction. If you make the mistake of picking up a mod with one on it by the mouthpiece tip, you'll end up spilling the whole tank and probably dropping everything in the process. I'll stick with T3s, Protanks, T2s and other delivery systems that get threaded together and stay that way.