If you're looking for versatility and a reliable atomizer, look no further. The Uwell Fancier Tank is a 2-in-1 system capable of RTA & RDA configurations. To swap to either atomizer system, the RTA configuration uses a Pyrex glass tube that creates a 4.0mL reservoir at the top, which can be refilled through the easy top fill port, and the dual post build deck on the lower half. The lower half of the device is transparent so users have the ability to observe the performance of their coil and cotton in action. The middle deck features wick holes that wicking material are to be fed through, creating an efficient downward wicking system from the tank to the coils. To use in RDA mode, the kit comes equipped with an RDA barrel that can be easily swapped in place of the RTA tank system. The RDA system also comes equipped with a spitback prevention design, reducing the occurrence of any hot liquid popping from the atomizer to the user.