This is really big atomizer named Iron Maiden and produced by Hell vape company. Do it your self Velocity base has 22mm and atty has 30mm. It can take upto 8,5ml of eliquid and it works like a charm. A lot of vapor and very nice flavor. Except one thing - top cap doesnt stick with atty body as well as it should. At all it is very good atomizer, but for that one con I cannot say it is must vape atty.