The Crown 4 (or Crown IV) is an evolutionary update on the Crown 3. The Crown 4 measures 28mm in base diameter and features sleek and smart design elements that combine for a universally appealing design. The Crown 4 features a 90 degree threaded top fill method that unscrews to reveal dual fill ports. The Crown 4 utilizes the new and improved Crown 4 Plug and Pull replacement coil style, with a threadless design that features reinforced seals to provide a liquid tight fit and finish. Each coil features a vertical coil arrangement and triple vertical wicking slots for rapid wicking. The Crown 4 Replacement Coils consist of unique materials such as the SS904L and the FeCrAl (Iron, Chromium, Aluminum) Coils. The Crown 4 Coil Family comes with a 0.2 ohm Dual SS904L coil head rated at 70 to 80W, a 0.4 ohm Dual SS904L coil head rated at 60 to 70W, a 0.25 ohm SS304 UN1 coil head rated at 55 to 65W, and finally the 0.23 ohm FeCrAl UN2 coil head rated at 60 to 70W. All in which contains organic cotton. The adjustable bottom airflow makes for smooth and effective airflow, and can be fully closed to seal the system effectively.