Machine Control Laser Detectors are mounted to heavy equipment (Backhoes, Trackhoes, Dozers) and they help the equipment operator know when he or she is "at grade". The laser detector will show them when they are at the level of the laser so they know either they need to take out more dirt (cut), or put in more dirt (fill). A rotary laser is mounted on a tripod somewhere on the construction site out of the way and the detector is mounted to the arm or bucket on the equipment. Machine Control Laser Detectors are usually larger than the normal detector, due to most rough grading jobs are of rough terrain, which means that you benefit from the detector having a larger"window" to detect the laser line. Equipment operators keep their eye on the detector and it indicates when its "on grade". Being "on grade" means you are "at level", or "on level". This is terminology commonly used in the field of excavation, grading, surveying, sitework, and construction.
