Abstract: A device for comparing dimensional proportions of at least two tapered objects, such as musical instrument reeds, so as to determine where a given thickness exists on one object, relative to the position of that given thickness on the other object. The device is comprised of a base over which two height sensors are mounted in such a way that the movement of one height sensor imparts a proportional movement to the other height sensor. A sliding double-edged reference bar and indicia on the base allow for the positioning and comparison of different areas of the tapered objects.