I forgot to mention that I really like the top cap as well. I'm using CE2's in a syringe mod and often got liquid leaking out of the battery end. I tilt, draw or just plain overfill too much, causing liquid to drain down the center air tube. The carto connecter on the Buzz prevents that from happening, as it seals up the battery end of the carto. The liquids stays in the carto and, so far, hasn't spilled over on to the juice well. It's like having a built in drip shield. I've even checked inside the connecter to see if their was overflow in there, but nothing. A little dampness but no flooding. My previous mod (Omega) had a recessed connection and no drip well. The connection didn't seal up anywhere near as good as the Buzz. I would often pick up my Omega and end up with liquid all over my hands. 3 days in and I'm very happy. My compliments to the engineer.