Please see this and other reviews - this laser level CANNOT be used outdoors in sunlight. Forget green light works in sunlight. This device does not radiate beyond 6-8 feet in sunlight. I put up fence posts in my backyard and had to wait until dusk (read absolutely no sunlight, almost completely dark) to film and be able to see the line. So it's completely useless for an external project. Was the unit correct? Yes. Can I use it internally? Yes, even during the day in diffuse light. But you can't use it outside unless you plan to do your project at night. Don't waste your money like me. Look for another laser level - this is not the laser you are looking for.