Cigarette and E-cigarette Nicotine Content in an Electronic Tobacco Marketplace (ETM)

Inclusion Criteria: * 21+ years of age * Self-report smoking at least 5 cigarettes per day for the past year * Breathe carbon monoxide (CO) level \> 8 ppm or positive urine NicCheck * Willingness to use other tobacco products during the study * Speak, comprehend, and read English sufficiently to complete study procedures * Have home access to a computer, smart phone, or tablet with a web camera and internet access * Tried a vaping device at least once in their lifetime Exclusion Criteria: * Currently seeking treatment to quit smoking * Self-reported serious medical or psychiatric condition(s) including cardiovascular and chronic respiratory diseases * Body temperature \> 100.4 F * Cold, flu or COVID-19 symptoms including fever, cough, and runny nose in the past 30 days * Currently pregnant, breastfeeding or intending to become pregnant for the duration of the study or unwilling to agree to use adequate protection to avoid pregnancy * CO reading \> 80 ppm