I'll try to clear it up a bit. The eGo and Riva 510s are batteries with a 510 connection. To drip you need a 510 atomizer. You can tailpipe it but, you'll probably want a 510 drip tip too. The eGo-T is just an eGo with a tank atomizer and a tank. You can take the tank atomizer off, put a 510 atomizer on and drip with it too. You can also put a tank atomizer and tank on a Riva and use it just like an eGo-T. I forget what PWM (Power Wave Modulated...maybe) stands for but, it means that the eGos are limited to putting out at most around 3.4 volts. I've seen conflicting stuff on the Rivas but, I think the new ones aren't limited and supposedly can go to 3.7 volts.