First off, anyone who watched Jai Haze’s review, ignore him! I was put off on buying this RDA forever because of it. Then I watched other reviewers who obviously know how to use a bottom airflow dripper. This thing is fantastic! Flavor is off the charts. Could not have been easier to build. Airflow is perfect and so easy to adjust. Wide open, plenty of air, not restricted at all. O ring tolerance is perfect. HAS NOT LEAKED YET. Just drip slowly and carefully like ANY bottom airflow dripper. Very nice build quality. I highly recommended this RDA!