These rulers are optimal for drawing curved lines when copying sewing patterns, creating drafts, or drawing curved seam lines quickly and neatly.
Parallel lines are marked along the edge of the curve, enabling the drawing of curved seam lines easily.
This is a set of two curve rulers and a mini ruler (15cm).

Instructional video: https://www.youtube.com/watch?v=3Du9dejrasU

CURVE RULER WITH MINI RULER