My first device was an Njoy Ncig set. This proved fairly reliable but I decided to add to my part collection so that I would never find myself without a working unit. I purchased 2 atomizers and batteries from a different merchant who is known for quality service and products. Ok so now I have the Ncig set which is 2 hole and the new equipment which is four hole. If i try and use one of the 4 hole batteries on the 2 hole vaporizer then it works fine. If on the otherhand I try to use one of the 2 hole batteries on the 4 hole atomizer then I might as well give up. I have to suck really hard to get the battery to light up and it stays on for no more then 3 or 4 seconds before turning off. One cannot produce a suitable amount of vapor with this combination. Has anyone else run into this problem? My guess is it is do to the switch and the amount of vacuum needed to activate. If you have found this problem yourself have you run across a solution? Thank you.