Alvin - Olfa - Steel Snap-Off Blades - 50 Pack - The Olfa Steel Snap-Off Blades are made of the finest tool steel. Blade in dispenser for Nos. OL-180, OL-SVR1, OL-300, and OL-A. These Blades have Thirteen snap-offs. Double-honed blades to 11 degrees. 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.