uMeasure Rebzar MS-80, Laser Distance Meter for Home and Outdoor Measure in Length/Area/Range Finder (0.2 mm -80 m/250 ft) emstrong/strong/emHow it works: a laser distance meter sends a pulse of laser light to the target and measures the time it takes for the reflection. Why not tape: a laser distance meter is on every count eg- speed, accuracy, safety, versatility, convenience, and functionality. Where to use: all kinds of measurements in construction, length, area. Non-verticle lines.