Wl21 pistol light has three types of lasers modes, WL21G, WL21R and WL21IR. The max output is up to 650 lumens. You can switch the dual light sources by the independent tail switches. witch is clear and simple. It's compatible with 1913 picatinny and Glock rails. Our innovative rail system allows you to install & remove the light single-handedly. It include one 16340 rechargeable li-ion battery, which can be charge directly by the usb port. When you need to charge, you don’t need to remove the gun light ,which is much more convenience and safety.