Unique heavy-duty, snap-off hook blade ideal for roofers, those cutting shrink-wrap and more. This blade made from high quality carbon tool steel is produced using a special process for sharpness and durability. Long lasting, durable snap-off blade - a new sharp edge with each snap. This 18mm blade fits most Heavy-Duty LB Utility Knives. 4 cutting edges per blade. 5 blades per pack.