Guido: These people who have responded to your post know what they are talking about. I have checked out their posts on a regular basis and they always make sense. I have over 140 units that here that we take care of. The company has strict rules on forklift,people movement through the plant. It is a high noise enviroment,and, knock on wood ,people just seem to look where they are going. We have the blue lights on all lifts that work inside the plant. They are on at all times,not just in reverse. We did some to see if they would work.They are great when a lift truck is backing out of a trailer. You have about 15 feet of warning space. Now they are on all units inside the plant. I also have to agree with what the techs are saying. You cannot hire an idiot cheap enough.