Round Wheel Ruler for measuring the distance of a curve. Example; measure curves around an armhole or neckline during custom pattern making. The ruler has an 20cm circumference. Double sided, so it has 1:4 measurements on the other side, if you are making a quarter sized pattern, you would use this. Use when an exact measurement is needed, a straight edge ruler won't bend around the curve, so use the rotating wheel to trace the shape.
