Exvape Expromizer V4 RTA comes with 23mm diameter and features a single coil deck. The RTA equips with the top filling cap and top airflow system, which prevents leakage effectively and refill easily. In addition, the Expromizer V4 tank utilizes an top-to-bottom airflow to achieve purer flavor. The e-liquid direct contacts with the cotton for better liquid flow. Enjoy excellent MTL vaping experience from it.