The Ba Gua is a 14500 battery mod. The switch and tube are laser engraved then polished to a beautiful shine. This mod is a perfect companion to any 16mm - 17mm atomizer, such as the Mini-b and many more. The Ba Gua is equipped with a magnetic bottom switch that is easily activated and a locking ring that effortlessly glides to lock or unlock the device. It is also equipped with a positive pin that has an independently adjustable 510 center pin and battery contacts to ensure a tight battery fit.