The Rockler Center/Offset Marking Tool straddles your board to mark a perfectly centered line along the face or edge of boards up to 1-1/2” wide or thick. Just insert your pencil into the center hole, rotate the tool so the guideposts contact the material, then scribe. Alternatively, you can use a pencil in the notches to mark lines from 1/16” to 1/2” from the edge in precise 1/16” increments. It’s great for marking out mortises and rabbets, or for making reference lines for drilling holes. The tool accepts standard wooden pencils and has an onboard pencil storage slot. An embedded magnet lets you store it on any ferrous metal surface, such as a power tool, tool chest or magnetic storage strip.