Late to this post, but Matt is right on the mark. Hopefully by now you have the slim "mini" Vivi Nova @ 2.4ohm. I've been using nothing but these for last two weeks. I can assure you, these are easy to fill, no leaks, and the tank is almost an all day vape. I have 4 and bought a 5 pack of heads. When I change liquid all I've done is rinse the wicks after taking it all apart and use a kleenex to dry the thing including the wicks. Refill and vape! As for the Twist, that's what it's for twist. You'll find the sweet spot with most juices from 4.0-4.4 volts. With the thread covers it makes your rig look really cool. Happy vaping!