The automatic turns on when you draw on the e-cig either by a vacuum from the draw or by the noise from the air being drawn in. The manual has a button you use to turn on the battery, you have better control on when the atty gets turned on and for how long. ie you can control the
vape better with a manual battery.
Also no hole in the battery to let
juice get into the battery and render it inoperable. The hole that the auto has to have to read the vacuum when you draw.
Most experienced vapors go for the manual for several reasons, I use it to get a better
vape.
Hope that helps, Elapid----<