The US Food and Drug Administration defines it as "Vapes, vaporizers, vape pens, hookah pens, electronic cigarettes (e-cigarettes or e-cigs), and e-pipes are some of the many terms used to describe electronic nicotine delivery systems (ENDS). ENDS are noncombustible tobacco products." "These products use an e-liquid that may contain nicotine..." and "the liquid is heated to create an aerosol that the user inhales."