The Vortex Optical StrikeFire Red Dot Sight boasts a maximum field of view by allowing you to keep both eyes open while you focus on your target. You get unlimited eye relief and quick target acquisition, plus there is no difference in the way the target appears. Even if the user changes position, the sight remains parallax-free past 50 yards. In addition, you can achieve and maintain a detailed view of the target thanks to the Optical 2x Doubler. Choose between a red or green dot on the Vortex Laser Scope depending on your surroundings and the conditions. Enjoy the fact that it's waterproof, fog-proof, and shock-proof, making this red dot sight from Vortex Optical easy to use in almost any type of environment and across most weather conditions. The battery lasts up to 2,000 hours, and it automatically shuts off after two hours to conserve power.