http://tinyurl.com/mvhwpc9 green laser usage:Field travelers, explorers? for outdoor lighting, indicating distant targets and send a distress signal. New features are: extremely cold extreme heat does not affect product performance; waterproof, moisture, sweat, water, wear-resistant features, particularly suitable for field use. Make your trip more fun interesting is the preferred equipment for outdoor activities.? amateur astronomers observing the starsMeans for astronomy satellite, laser light emitted will draw a beautiful ''green'' in the night sky, it is suitable for observing the night sky, can accurately indicate the position of the stars. Direct target airspace, very spectacular.? mining sites, construction sites and related personnel