Product features: Top cap, tubes and switch assembly are machined out of solid copper Hybrid connector design means direct atomizer center pin contact to the battery positive post - your atomizer center pin MUST be exposed or a short will occur Lock ring is made from brass and firing button from stainless steel 22mm diameter size fits flush to most any 22mm atomizer Comes with THREE tubes to fit 18350, 18500 and 18650 battery cells Recessed firing button is very smooth and won't fire when set down on a flat surface Specially designed lock ring is nearly impossible to seize from over tightening Solid copper design means high conductivity and low voltage drop Each switch is serialized on the inside so you can polish the mod as much as you want and not damage the serial number Batteries not included Spare insulator o-rings included