Zebralight VERY HIGH-Performance ZL634 3400mAh 18650 Protected Li-ion Rechargeable Battery (Panasonic NCR18650B) for Supercharged Flashlights e-Cigs PROTECTED 3400mAh Panasonic 18650 li-ion 3.7V battery by ZebraLight - The latest Panasonic NCR18650B 3400mAh cell is used to build 18650 3400mAh Zebralight protected battery. Protection: Over-current (Activated @ 10A-12A), Over-charge (Activated @ 4.35V) - Over-discharge (Activated @ 2.5V) - Over-temp. and DUAL short circuit protection (External, and Internal).Protection circuit designed by Seiko. ICs made in Japan. Best battery for High-Power flashlight users, or for anyone who is looking for the longest run time possible. This is the largest REAL capacity available on US market. Very safe to operate, This 18650 Li-ion protected battery will auto. disconnect itself from el. circuit in case of: Short circuit - Extreme temperature, Abnormally high current , Over-voltage - Over-charge, Over discharge. Battery cell: Panasonic NCR18650B, Capacity (Ah): 3.4 Ah (3400mAh), Charging Voltage (V): 4.2 V, Energy (Wh): 12.2 Wh, Energy Density (Wh/L): 730 Wh/L, Nominal Voltage (V): 3.6V - 3.7V, Weight (g): 46 g, Diameter (mm): 18.6 mm (+/- 0.03), Length (mm): 68.9 mm (+/- 0.03) -- Top Button (Positive) made of Nickel (Ni) - Negative made of Copper (Cu) for an ideal conductivity, and durability.