It is HIGH POWER green laser pointer.This is the best astronomy educational tool you've seen. At night this AAA battery powered green laser pointer can seemingly touch the stars millions of miles away. Compared to a red laser pointer, the green beam remains visible and penetrates the air much farther. Because of its particular spectrum you see the beam and not just the end dot. Also, it's about 50 times brighter than an ordinary red laser pointer -- using the same safe low power. On a clear night it can easily shine a dot a mile away. With its sharp laser beam you can pinpoint the exact star you want, which greatly accelerates mapping and learning the constellations.