The Mule Light is the only flashlight you will ever need. It combines all the functions of traditional flashlights and something totally new! Just cover the LEDs with the reusable glow stick and turn the LEDs on for about 3 seconds. You just charged the glow stick, which has rechargeable crystals inside. Now use the glow stick as your light and save your batteries for when you really need them. Turning on a regular flashlight in the dark can destroy your night vision or draw unwanted attention to your location, so this flashlight features a stealth function by including black lights. The flashlight comes with two battery pack options – 3 AAA batteries (included) or a USB lithium ion rechargeable battery.