Alvin - Rolling Ruler - 12 inch - The Alvin Rolling Ruler is a multi-purpose drawing tool made from high-impact plastic for students, artists, and designers. Graduated in both inch and metric. Includes many useful formulas and conversion factors. The Alvin Rolling Ruler helps you draw horizontal and vertical parallel lines with ease. Draw circles, curves, or arcs. Use the built-in protractor to draw angles. Blister-carded, instructions on back. Alvin is one of the primary sources for drafting supplies and drawing equipment in the country. Creative Coldsnow is a pround retailer of Alvin graphic arts, drafting and fine arts products.