Samsung 21700 4000mah battery
Rated capacity: 4000mah
Rated standard discharge capacity: 3900mah
Rated max discharge current: 30A
Nominal voltage: 3.6V
Peak voltage: 4.2V
Fully charge before first use.
Never short (connect positive and negative size) battery.
Keep them always in battery case, or any other insulating material.
Never keep this battery together with metal objects (short circuit can happen if you do).
Never carry bare cell in your pocket with keys, change or any other metal objects.