This battery is from 3 experiments with 2100 mAh to achieve a longer duration. No Success. Initially, the batteries seem to actually run longer, but (despite manual) after 3 charging cycle they keep (also this battery) barely 1-1.5 days. the "original" -Samsung 1900 mAh battery schafftda something more. But in this "battery king" is at least one hot will not be felt both in everyday use and during charging. It's good. Good performance. / Longevity ??