Flat head 18650 lithium battery 3.7V (length 65MM width 18MM). Output 5V 2A (two ports current 2A). Both USB ports can support fast charging (only when one is used alone). Flat head 18650 lithium battery 3.7V (length 65MM width 18MM), pointed flashlight battery and battery with protective plate are not available (No. 5 and No. 7 batteries are also not available).
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