Alvin - Olfa - Professional Utility Knife - The Olfa Professional Utility Knife is a slim-line professional model for draftsmen and designers. Olfa Professional Utility Knife includes one blade. Uses OR-AB10B, OR-AB50B, OR-AB10SB, OR-AB50S, and OR-A1160B blades. 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.