The Vaporesso GT core coils are designed for their NRG tank range however are also compatible with the likes of Smok baby beats tank and others.
All coils are priced and sold separately.
GT2 - 0.40 ohm - 40-80w/ Best 55-65w
GT4 - 0.15 ohm - 30-70w/ Best 45-60w
GT6 - 0.20 ohm - 40-100w/ Best 70-90w
GT8 - 0.15 ohm - 50-110w/ Best 60-80w
GT cCell - 0.5 ohm 15-40w