The AMP 3W LED Weapon Light is an excellent illumination tool to give yourself an advantage over your opponent. The ultra brigth LED light puts out a power white beam of light with less energy than an equally powerful incandescent lamp. This light is powered by 1 CR123 Lithium battery and has a built in mount into its body. The activation switch allows the user to choose between momentary and constant on/off. This light is made for pistols but can be used on anything with a 20mm rail.