The reasons for this are a) it was written by engineers and b) the binocular was intended for both bow- and rifle hunters, and was designed to compute not only shots taken on the flat, but also angles. To get it to tell me the distance to the target in yards was more than I could do. Also, the LED display was so dim it could not be seen in daylight, and I was unable to crank it up to full power. The neck strap, even when shortened as much as possible, left the glasses swinging down around my belt buckle. Otherwise it was fine.