Comparing Nicotine Delivery, Subjective Effects, and Sensory Experiences of Tobacco Users Using Oral Nicotine Products and Electronic Cigarettes [ZYN Study]

Inclusion Criteria: * Current daily cigarette smoker as determined by: 1. Smokes \>5 cigarettes/day for \>1 year OR 2. Current daily smokeless tobacco or oral nicotine user as determined by: a. Uses \>=5 units/day for \>=1 year * b. Uses portioned moist snuff, loose moist snuff and/or nicotine patches * Willingness to abstain from using cigarettes/ST (smokeless tobacco) for 8-10 hours (overnight abstinence) prior to study visits (verified by exhaled-air carbon monoxide \< 10ppm). * Self-report fair or better physical health. * Self-report fair or better mental health. * Participant must understand the investigational nature of this study and sign an Independent Ethics Committee/Institutional Review Board approved written informed consent form prior to receiving any study related products Exclusion Criteria: * Currently uses other tobacco or nicotine products (e.g., ENDS) \> 2 days/week. * Self-report having active, untreated medical/psychiatric conditions History of serious side effects from nicotine or from any nicotine replacement therapies. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. * Nursing female participants. * Vulnerable populations, such as cognitively impaired adults, individuals who are not yet adults, pregnant women, and prisoners. * Unwilling or unable to follow protocol requirements. * Any condition which in the Investigator's opinion deems the participant an unsuitable candidate to receive study drug. * Previous use of the study products (ZYN or Vuse Alto; on! or General Slims).