Alvin - Paral-Liner - Parallel Straightedge - 42 inch - Alvin Paral-Liner Parallel Straightedge has rigid phenolic construction with a black satin finish. Mobile straightedge affords frictionless operation through the floating action of the nylon rollers mounted on the blade. The Paral-Liner Parallel Straightedge rollers retract at a touch, securing the blade for accurate drawing. Acrylic edges are elevated to prevent ink smears and steel ball-bearing pulleys provide smooth movement. Parallel Straightedges come with all mounting hardware and installation instructions. 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.