The G2Z is almost identical to SureFire's best selling aluminum Light, the Z2, which has become standard issue for the FBI, U.S. Air Marshals, and police departments worldwide, as it is bright enough to temporarily blind. Constructed of Nitrolon, a corrosion-proof proprietary polymer that absorbs shock more efficiently than aluminum, the new G2Z shares all of the best features of the best-selling Z2 Light, yet is lighter and more water-resistant. The G2Z is powered by two lithium batteries (10-year shelf life). Although three to four times brighter than a much larger two D-cell flashlight, this lightweight powerhouse is less than five inches long, making it ideal for those times when space is at a premium and weight is an issue. The G2Z also features unique switching originally developed for law enforcement twist for constant on, or depress the tailcap button for momentary illumination or emergency signaling.