Hmmm, a cartomizer should just be one piece.
I use cartomizers for the Kr808, but it's pretty much the same thing.
A cartomizer has a wire (the heating element - basically an ultra-simplistic atty) running up
through the middle of it, with a wicking sock wrapped around it. And around that is filler material. The filler material holds liquid, which soaks into the wicking sock, which vaporizes when the wire heats up.
It's all one piece, one end screws onto the battery and the other end is the mouthpiece.
Are you sure you got cartomizers? I'm a bit confused... Atomizers don't have a screw top - you just push the cart into the open end. But cartomizers screw in. So I wouldn't think it'd be possible to insert a cartomizer on top of an atomizer...
Look inside the cart/carto. Is it just filler? Nothing else? If it is, it's a regular cart. If it's not, I'm confused.
