The Slope is a function of a golf rangefinder gadget that allows you to measure the slopes of a golf court using the instrument. When planning a course for a competition where rangefinders are not permitted, it is helpful to consider the Slope of the terrain. I recommend using a standard rangefinder because it does the job and is legal for most tournament play. A slope is preferable if you want to use it for casual rounds or practice since it makes the shots more manageable. It all comes down to whether or not you would like to spend more on the slope feature.