This is an atomizer section for the DSE901 Electronic Cigarette. It is always good to have a couple extra atomizers laying around just in case yours ever gives out on you. Also, some people like to use different atomizers with the different flavored cartridges so they dont get a mixing of their flavors. Some want an additional atomizer so they can use it with their additional battery that comes with the starter kit so they have two full Electronic Cigarettes. Whatever you may need it for, it is here.