Extra Heavy-Duty Snap-off Blade, 5-pack (HB-5B) - Good For: cutting drywall, roofing, leather, rubber, etc. High quality blade with superior edge retention. Extra-heavy-duty, snap-off blade for the toughest jobs. This blade made from high quality carbon tool steel is produced using OLFA"s precise multi-step production process for unparalleled sharpness and superior edge retention. Long lasting durable snap-off blade - a new sharp edge with each snap. This 25mm blade fits OLFA Extra Heavy-Duty Utility Knives. 7 cutting edges per blade. 5 blades per pack.