The Surge tank on the ego works but looks a bit strange. I think it is the best way to vape if you have little kids and are on a shoe string budget. The surge hold the juice where kids can't get to and you just need to push the bottle every couple of drags and get the great atty draw and flavor. I pefer the voltage and battery life of the surge on GLV 2 XL. It went great on my darwin when I still had it. It makes any mod a bottom feeder. It is a must have IMHO. You can read more about the surge and how to get one here