The pitch is the most important property of a propeller that you can select from. It is in fact the “curvature” of the propeller blades. The pitch (e.g. 17) represents the forward distance (number of inches) which a propeller would make in a complete rotation.
A smaller pitch means less curvature and more acceleration, a larger pitch means more curvature and potentially a higher top speed. We advise to not deviate too much from the standard pitch that is mounted on your engine, because this could actually result in worse performance. For example, if you choose a too high pitch, your engine may not reach the optimal RPM and therefore actually result in a lower speed than before.