RDA / RBA
A Rebuildable Dripping Atomizer (RDA) is a rebuildable deck covered with a cap and drip tip that can be removed in order to drip e-liquid directly on the coils and wick. RDAs have no tank for e-liquid, and must be dripped on after every few uses; however, with no surrounding tank almost the entire width of the device can be devoted to build space.
A Rebuildable Dripping Tank Atomizer (RDTA) is simply an RDA with a tank section underneath. Instead of sitting on the base, the wicks are passed through holes in the deck into the tank. This combines the space given to an RDA for building, with the convenience of an RTAs e-liquid reservoir, while allowing to still drip directly on the coils.