Get more done using fewer blades with Fiskars Pro CarbonMax Snap-off Utility Blades. These blades were specially designed using a unique carbon-bonding process that helps them stay sharp up to 24X longer than standard utility blades, for the industry’s best blades. CarbonMax blades’ edge-retention coating has been laboratory tested and verified to stay sharp even after heavy use. Compatible with most 18mm utility knives.