It may have been a poor naming choice since TW has given the "Mega" moniker to represent longer/larger products. The Mega Carto's from Nhaler are the same size as most others, just a higher resistance, or at least tend to be higher than normal, over the 3.0 point which makes them great for 5-6v. They're the same size as the ones I received from Eastmall, but also from the differences between EM and Nhaler, the Nhalers do have more filler, soaking up some more nummy liquid.
I get around 25-35 drops in them depending on liquid, pure VG drops tend to bring the total down but it seems to always rest around 1.2ml per fill, and I don't have to deal with condom filling... as I also get to keep doing my retentive need to drip into the atomizer.
Eastmall ones when I had to refill, was more around 20 drops.