Abbreviation for "MilliAmp-Hour". A common measurement of how long a battery can supply power. A milliamp is one thousandth of an ampere. A 3300mAH battery cell is 3.3 ampere-hour, which will provide 3.3 amperes for 1 hour. A 650mAH battery cell will provide 0.6 amperes for 1 hour. Then multiply by the number of cells. A 6-cell 3300mAH battery pack will provide 19.8 amperes for 1 hour, or 3.3 amperes for 6 hours. Generally the higher milliamp rating, the longer runtime you will receive.