An RDA stands for Rebuildable Dripping Atomizer. An RDA is a type of RBA that requires the user to manually add juice to the coils and wicks, instead of being fed from a tank. RDAs have a juice well at the bottom of the build deck to hold e-liquid, and the wick tails are placed into the well. Generally, the juice well does not have as much capacity as a tank, so the vaper must continuously add e-juice ever so often, to prevent the wicks from getting dry.