OLFA premium utility snap-off blades are made of the finest quality tool grade steel. Each blade undergoes a special multi-step production process to ensure unparalleled sharpness and superior edge retention. This makes OLFA blades virtually unmatched in their initial cutting power and edge retention. They are ground, then specially honed for maximum cutting performance. Ultra-sharp black blades are double honed to produce an edge that is 25% sharper than OLFA standard silver blades. Segments are angled to a precise 59 deg which complements the natural position the hand assumes when cutting. This precise angle helps prevent the blade from breaking during use. The cutting edge of OLFA snap-off blades can be instantly and easily refreshed upwards of 13 times ï¿½ simply snap off the dulled segment for a fresh edge. The snap-off blade also offers an advantage in material cost savings by providing up to 13 edges versus the two of traditional utility blades. Use these heavy-duty blades on construction materials such as linoleum, carpet, flooring, insulation, roofing, and much more.