i have NO 7 micro batteries left over and some 4081 blank cartomizers i had bought thinking they would work and they would not work, if it is the micro no 7 kit we are talking about. They look very close but the threading is a bit off just double checked them just now to make sure i was correct and they will not fit.. look at the ljesmoke site for what are compatible this is what it says

only named this site because it is the only place I have ever seen any NO> 7 compatible items)
these cartomizer will not fit 510 batteries, they are compatible with No7 Micro and 601C models. They are 7.50 for a pack of 5 blanks..
I hope I am not coming off as a know it all because all I have learned about these wonderful devices has been from this forum

and still learning on a daily basis !! ..but when I was using these I searched high and low looking for compatible stuff and could find nothing other than what they sold at the NO. 7 site . I would have been excited to find blank cartomizers as that is what I was looking for.. I ended up going to 808 and 510 compatible stuff just for selection... good luck to you I hope you find what you need...