Heavy-duty utility blades are heat-treated for durability. The blade-grinding geometry is designed to deliver first-cut sharpness. Each pack contains 5 blades. They are constructed to be used with most standard utility knives.Grinding geometry offers an edge that is 35% sharper performance and accurate cuts from the start of workInduction hardened cutting edge allows 75% longer cutting for fewer blade changesSpecially heat-treated blades that are 20% stronger durability and less blade changes