The Zeus RTA by Geek Vape is hands down, one of the best RTA's on the market. It utilizes a unique top-airflow system that allows you to change your coil even if your tank is FULL! The Zeus is a single coil device that still creates the cloud that you've come to expect from these devices.
The GeekVape ZEUS RTA is 25mm in diameter and fits nicely on most, if not all, of today's mods. With a 4ml vape juice capacity, you won't have to fill up as often as other devices.
Not only is this RTA functional, but LOOK AT IT! It's a beautiful addition to your favorite box mod.