Looking for a Li-Ion for flashlights, I first came across the 4000mAh - cells. When the arrived; oh Grauss: A cell made it just on 700 mAh, another at 450 mAh. How can you think that since 4000 mA should go in too! So I ordered with many doubts about the two brand cells from Samsung. Once there, ran to the computer charger, lower cutoff 3.0V, upper 4.2 V. And: Capacity 20 to 30 mA at 2600 mAh. Super Battery! But be careful, the battery does not have an undervoltage lockout. Therefore, rather often invite. Undervoltage is death of each lithium battery.