 The studys aim is to develop a clinical model that can be used to measure the nicotine delivery and tobacconicotine abstinence-suppressing capability of electronic devices that are marketed as a means to deliver nicotine to cigarette smokers. The study will compare the nicotine delivery, cardiovascular effects, and tobacco withdrawal suppressing effects of two devices currently marketed in the U.S.: Crown Seven and NJOY. Specifically, the effects of these devices will be compared with the effects of own brand cigarettes positive control, and an abstinence condition sham smoking; puffing from an unlit cigarette. The primary hypothesis is that the nicotine delivery, withdrawal suppression, and other effects of electronic devices marketed as a means to deliver nicotine to smokers can be measured during a period of acute exposure. 