Uwell Crown IV Dual SS904L Coil utilizes high-quality steel and organic cotton, 0.2ohm and 0.4ohm available. Both of them have a long lifespan and offer you a better flavour. The dual SS904L coil is only designed for Crown IV tank. 4pcs in a pack. Uwell Crown IV Replacement UN2 Mesh Coil features 0.23ohm resistance, it can enhance flavour than the regular coil. It is designed for Crown 4 / IV tank. 4pcs in a pack.