I just started vaping a week ago and just bought my second ecig. I started out with a kit from Esmoke which I paid way too much money for and amm going to try and return it because it is a total piece of crap that my wife said smelled like piss. I just went to a shop looking for some cartos and found a 901 kit so I bought it. My question is what is the difference between the 901 and 510. I've read that 510 drip tips fit on a 901 so what else fits it? Can a 510 PT work? Etc. BTW So far I love the Atty over the Carto even though its just been a few hours.