OLFA 18mm Heavy-Duty Ultra-Sharp Black Snap-Off Blades are the solution for precision cutting. Premium Japanese carbon tool steel provides durability. Dual-honed black blades are up to 25% sharper than standard silver blades. Each blade offers eight (8) segments per blade for volumes of accurate cutting action. Each segment has deeply etched grooves for easy, clean breaks. When a segment is dull, a simple snap supplies a fresh, sharp edge. The universal 18mm size is compatible with most 18mm handles.