Joyetech AIO / BF Kits are equipped with coils in a range of resistances - 1.0, 0.2, 0.5, 0.6, and 1.5 Ohms. To change the coil, first unscrew the cap of the Joyetech AIO and then unscrew the coil unit. Put the new coil in place on the cap section. Before using, it's important to prime the coil by applying a few drops of e-liquid directly to it, allowing for a 15-minute soaking period. Note that overfilling the AIO tank can result in liquid displacement when replacing the child-proof cap, so be sure to heed the filling indicators.