The UD IGO-W3 RDA is an excellent rebuildable atomizer with unbelievable flexibility. The five-post design and adjustable airflow will accommodate anything from a single-coil, dual-coil, and quad-coil builds! 22mm size fits all your 18650-sized mech mods, as well as all your standard box mods. The stainless steel construction is durable and beautiful, while the simple design is timeless. Put one on top of your favorite mod today!