A rangefinder is an essential part of a junior golfer's equipment and the Nikon Coolshot 40 rangefinder is a proven and very popular option with junior golfers. The benefits of rangefinders and the factors that need to be taken into account when considering buying a rangefinder are covered in detail in Best Range Finders for Junior Golfers.
The Nikon Coolshot 40 is the most powerful USGA approved rangefinder in the Nikon product line. It is simple to use and with the push of the Power button, the First Target Priority mode kicks in and allows for easy distance assessment to bunkers, fairways, trees, ponds, and the flagstick. Hyper Read provides quick and stable measurement response, in approx. 0.5 second, regardless of distance to the target. It has 8 second continuous measurement scanning which allows quick measurements to multiple targets and sophisticated optical technology which provides clear images from dawn to dusk.
The reviews of this rangefinder show that the product is easy to use and good value. It is a bit on the small side making it more difficult to keep steady (which will affect the junior player more) but reviewers have found it favorably comparable to the Bushnell.