The Acme United ACM16930 plain-edge double-bevel school ruler is great for drawing straight lines and measuring. One bevel features a horizontal portrayal of relationships between mm, cm and dm, while the other bevel has regular mm scales with numerical cm markings from 0 to 30. The ruler is 12" long and has grooves in the crown. | Acme United Plain-Edge Double-Bevel School Ruler (ACM16930)