GoVolt A4 uses two 18650 rechargeable lithium ion batteries and includes a duel charger. This flashlight has 3 modes from high, low, and strobe. The strobe mode is useful for emergencies if you have car trouble. It is effective at disorienting people incase you encounter an intruder in your home or outside in the public. Another feature is the zoom focus. Push the head of the flashlight for a narrow focus that has a high-intensity spot beam. Slide the head back for a wide focus and it will brighten up a larger area. This flashlight is essential for outdoor enthusiast .