Berlinlasers Green Dot Laser Alignment for Easy Dot Targeting When green dot laser alignment gets constant electric power source from DC input power supply, it keeps constant green reference dot positioning on all targeting surfaces efficiently. It gets wide range output power of 5mW to 100mW, equipped with 3V or 4.2V DC input power supply, it gets continuous green laser dot positioning with the maximum dot aligning distance of 25 meters. Only if it is properly installed and adjusted, this green laser module gets the most efficient dot positioning result precisely. http://www.berlinlasers.com/532nm-green-dot-projecting-laser-alignment