As its name indicates, the Vortex Ranger 1800 Rangefinder is capable of ranging targets with great precision out to 1,800 yards - more than a mile! It gives hunters and long-range shooters the ranging data they need to make precise shots confidently, or to know when NOT to take the shot because the target is out of range. With its clean, uncluttered display and easy-to-use, intuitive menu, the Ranger 1800 keeps things simple, yet provides a high level of performance. Its Primary HCD (Horizontal Component Distance) mode displays an angle-compensated distance reading that boost your accuracy when shooting on uneven terrain. Or select LOS mode to get a reading of straight line-of-sight Mfg: Vortex Optics