Alvin - Drop Bow Pencil Compass - 4 3/4 inch - The Alvin Drop Bow Pencil Compass is for pencil use only. Sturdy fiberglass construction with tarnishresistant chrome plated steel parts. The Alvin Drop Bow Pencil Compass is for rapid, precise drawing of circles up to 1 inch in diameter. 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.