From the makers of the Alliance V1 & V2, 28.5mm BigBoys, and the enormous 46mm FatBoy, Vapergate brings you the Mason RDA.  The concept behind the Mason 40mm is simple: get back to basics. There are no clever air hole patterns. No vortex or swirling air flow. No bottom or top airflow. The mason offers dual tiered, focus directed airflow straight to the coil with a continuously variable triple tiered air flow control ring. Staying true to the uni-post deck design, the negative posts are dug out leaving even more space for coils and cotton configurations.