Laser Range Finder-NSLRF501 Ideal for hunting, outdoor sports and commercial uses. Laser Range Finder is able to measure the distance as by emitting invisible, eye safe, infrared energy pulses to the target and instantaneously calculates ranges by measuring the time it takes for each pulse to travel from the range finder to the target and back. Range finders ability to measure the distance is determined by the distance and the size of the object. Measurements can also be effected by the colour, surface finish, size and shape of the object. The NSLRF501 has a scan feature that allows you to make several measurements with one scan.