I just got a 510 to leo atomizer adaptor and I am glad I did . The cartomizers for the leo at least the stock ones I had where 4 ohms or so . The 4ml capacity is good but the resistance is too high well now with the adaptor and a provari I can vape at 5.5 volts so the high resistance is no problem . Vapingzone also seems to sell the Leo cartomizers but they are 2.4 ohms as they probably should have been in the first place . The cartomizers from VZ have LR on them . I have not tried the Leo atomizers on the provari yet I don't use them much anyway .