this item High end alloy steel plus precision double honed edges make this blade up to 3X long lasting and durability than other traditional carbon steel blade Durable & Sharp,They are made from SK5 steel, which is well-built and durable.It is very sharp and easy to cut a lot of material. Ideal for cutting cardboard, leather, linoleum, laminates, rope, soft metal, carpet, rope, plastic, rubber, scoring sheet rock,etc. COMPATIBILITY: utility knives and other standard utility knives