Freemax Fireluke 4 Tank Features: 25mm Diameter 28mm Widest Diameter 5mL Tank Capacity Sliding Top Fill System - Single Fill Port Freemax Coil Series 0.15ohm X1-D Coils 0.2ohm X2 Coils Threaded Coil Installation Dual Slotted Bottom Airflow Control Ring Threaded 510 Connection Available in SS, Black, Silver, Blue