I was told that Eleaf coils are compatable with the Smok Big Baby tanks. I was skeptical at first but decided to drop the money on a pack because I was also told that they make the juice taste better and they are considerable cheaper then the Smok coils. Well sure enough, the Eleaf coils do make my Vaping taste a lot better and my wallet loves the cheaper price. I replaced the 0.4 Ohm Coil that is good for 40 to 80 watts (It is suggested on the Smok coil that it works best between 55 and 65 watts) with a HW4 - 0.3 Ohm Eleaf coil that is good for 40 to 110 watts. I just happened to notice the difference in allowed wattage so I cranked my Majesty up to 85 watts and Wow, what a difference. The coil did not get as hot as I exoected and the taste was out of this freaking world. I have 6 BB's and they all will get a coil make over as juice permits. Anywhos - I also have a couple BBB's that have the Q2 0.4 Ohms coil in it and would like to get some Eleaf coils for them. Does anyone know what size Eleaf coil I need to get to replace the Smok coil in these bad boys? Any inout is greatly appreciated.