And i love them!! What a difference. I realized that when i was filling cartridges, i was only using the first few drops off the top. I had to stop and top off the cart every 15-20 minutes and play around with polyfill. I found out a cartridge would hold about 12 drops. That means if i was adding 3-4 drops to top it off everytime then i was wasting 2/3 of my juice. Not doing that anymore. The tanks have no polyfill and use every drop of juice i put in them. You get a consistant flavor and vapor everytime as well. I also got some clearomizers to try out. We'll see how they work soon.