Laser distance measures are alternatives to traditional metal tape measures; they're used to calculate lengths, widths and heights of up to about 650 feet (198 meters). They're generally considered accurate to within an eighth of an inch (3 millimeters) when measuring a distance of up to 300 feet (91.5 meters). Laser tape measures are used mainly by contractors, insurance adjusters, architects, flooring professionals and other people who do a lot of measuring. Read Less