I'm not a big carto fan, I prefer my RBA's, but I must say that these double-punched Boge 3.0 XXL cartos that came with my new Mom and Pop sub tank sure work really well. I wanted to try the side-fill sub tank because I read that the grommet set-up was somewhat superior to the the standard tank sealing method and I would have to agree. I don't think I would use these cartos w/ a 3.7 V APV but they work great on my Opus at about 7 watts and I'm looking forward to trying them on my 5V-R Bogger Box when it arrives. The Boges seem to suck the juice consistently w/o over-saturating the filler. I have yet to get a dry-hit and that burnt filler taste. Just thought I'd throw my in.