Carto type for an Ali'i

I recently obtained a VV Ali'i from a classified transaction. I was in posession of a set of cartomizers from another transaction and these particular cartos have slots cut out in the 510 threaing as opposed to the pin holes above the threading in the other cartos i have. What i have found with the cartos with the pin holes when using with the Ali'i is that when i screw it down the pin holes are totally closed off and i can't get a drag. When i use the carto with the slots it works perfectly. Does anyone know if these cartos with the slots in the threading have a particular name and where i can get more? Thanks in advance.