The working situation with two 123A batteries as follows:
One 123A battery after being fully charged is 4.2V, two 123A together is 8.4V. When one 123A battery is consumed to 3.2V, that is to say, when two 123A batteries is consumed to 6.4V, our e-cigarette will be automatically close, that means it can’t work when it is lower than 6.4V, so we say our e-cigarette’s work voltage with two batteries is: 6.4V-8.4V
PS: our e-cigarette can automatically recognize to work with 18650 battery or two 123A batteries.
When working with one 18650 battery, the work voltage is: 3.2V-4.2V.