Two Ultrafire® brand 18650 rechargeable batteries for powering the Survival Laser I, 1.4 or II. Use two of these batteries with the battery extension tube accessory (P/N SL-BET1) for maximum output power. Note: The Survival Laser flashlights use only one (1) 18650 battery.
Capacity: 2400mAh (manufacturer rating)
Voltage: 3.7V (4.2V at full charge)
Protection circuit: No