Blue works. only problem is, they are expensive. two packs of Marlboro is around $11 here. single Blu disposable is $12.50. and i went through Blu in about 2 days. two packs or Marlboro last me about 3-4 days. so i read up on mechanical mods and RDA and placed order for them. the initial investment is around $100 or less. that's mod, atty, wire, battery, battery charger, cotton, and e liquid. you will need some sort of multimeter or something to test your coil set up. there are warning signs of using mech mod all over the place. you really need to read up on how to set them up properly. if you draw too much from the battery, they can go boom. only way to control the current and all the electrical thing is by building the coil that can have proper resistance. and getting right battery isn't as easy as it sounds. too many fakes out there from what i'm reading. i still haven't ordered battery and the chargers. charger is the easy part. but battery.. there's efest which is repackaged LG or Sony..there is Sony which fakes are all over the place.. there are LG and Samsung which are not rated as high as Sony.. after reading ton about them, i'm leaning towards LG or Samsung. i'm planning to build coils are .7-.8 ohm and that will run far under 20 A they are rated for. just sitting around and waiting for the shipment to come in.. it will be around mid Nov.. yeah.. ordered it from FT,and all the things i wanted (meaning cheap) are on 7 day shipping delay.