I think Vapor4Life should produce a big battery mod like the iGo. It's a KR808 device and the battery lasts 2 to 3 days depending on usage before recharging. There are soooo many big battery mods out there that are 510 devices but not enough KR808 big battery mods. I use the iGo ecig and it's awesome! You don't know vapor production unless you try it yourself. I mean BIG clouds of vapor and perfect throat hit and taste depending on flavor and nicotine strength.