The answer is all of the above. Since their creation in 2003, electronic cigarettes have taken on many shapes and forms and are still evolving today in appearance and functionality. The term "electronic cigarette" (e-cig), although an improper name, was coined because the first models were made to look like and deliver nicotine in a way similar to a cigarette. Where cigarettes delivered nicotine into the body through the inhalation of smoke via the burning of tobacco, the electronic cigarette delivered nicotine into the body through the inhalation of a vapor created by heating a liquid solution.
Many e-cig manufacturers however, offer nicotine-free products as well, essentially making them flavored-vapor devices. Other names that apply to an e-cig are vaporizer or personal vaporizer (PV), electronic nicotine delivery system (ENDS) or electronic nicotine delivery device (ENDD).
The e-cigs/vaporizers can be classified into three categories based on the main components involved in producing the vapor. These are atomizers, cartomizers and clearomizers and can be found in a wide selection here at VapersandPapers.com