The French curve is used to draw a smooth line through predetermined points. 

1203S: French curve set, Contains three of the most popular curves, packaged in a vinyl bag. Made of acrylic-topaz, each one offers a double-beveled inking edge to prevent smudges and a tempered, scratch-resistant surface. Sizes are 5.5" (14 cm), 6.5"(16.5 cm), and 12.5" (32 cm). Ideal for all design works, such as drawing office, craft workers, students and general design work