- Abstract During an adiabatic pumping cycle a conventional two barrier quantum device takes an electron from the left lead and ejects it to the right lead. Hence the pumped charge per cycle is naively expected to be $ Q\le e $. This zero order adiabatic point of view is in fact misleading. For a closed device we can get the counter intuitive result $ Q\gg e $. In this paper we illuminate the physics behind this mathematical observation, derive a practical estimate for $ Q $, and explain that the result is not merely a formal one.