I bought this rangefinder for birding, to be used to estimate both size and elevation of birds in the field. As this is my first laser range finder I have made a series of calibration measurements at near horizontal to make my own judgement as to the line-of-sight accuracy. I made 25 measurements against distances of 97, 126, and 265 ft (32, 42, and 88 yards). All together I found very high accuracy with a standard deviation of 0.35 ft (or 0.12 yd). Very high accuracy.The unit has three modes, Scan, Golf, and Speed. I am disappointed to find that in Scan mode it only displays the line-of-sight distance. I would have liked to have the inclination angle displayed as well.In Golf mode the unit displays both line-of-sight distance as well as inclination angle and a sort of calculated golf distance that I do not understand or need (it is NOT a calculated horizontal distance). It takes about 1 or 2 seconds for the reading to display. this is the only way to get an inclination reading.In Speed mode it appears to calculate the speed of an object. The manual helpfully notes that this can only be used "in condition of coaxial". That is to say, if you are standing on some railroad tracks and a freight train is headed your way, the Speed mode will give you the needed data in order to calculate how much time you have left to live. Other than that its pretty useless.I give it only 4-stars because the inclination is not displayed in Scan mode.