Buy a Open Center Protractor, 6 Ruler Edge, Clear Plastic, Dozen online at a discount. For additional info or to view another item in this category, click next item. To return to where you were, use the current page links below. Drafting Tools and other engineering tools can be found in the Engineering Book Monster for a discount! 50 Drafting Tools references are alphabetically sorted. Click on items for descriptions, reviews, price info, and more information. Also shop at Engineering Book Monster for textbooks on engineering theory and practice. Use our database search tool to locate specific titles, authors, and disciplines.