A distance measurer is the perfect device for realtors, builders, and DIY enthusiasts. Using one of these units will quickly give you the length, width, and height of any room. You can also measure the volume of an area. Measurements are displayed on an easy to read LCD screen. The best distance measurers will have a built in leveler to help you keep it straight. Many use laser or infrared lights which allow you to determine long lengths while standing still. Light-based devices have limitations, but are usually able to measure lengths as long as 18 meters.