You'll find that, because OLFA blades are so durable, that this 20-pack of blades will last you quite a while. Use these blades for cutting industrial materials such as gaskets, conduit, belt synthetics, rope, leather, laminates, plastics, fiberglass, rubber and textiles. Good for applications such as general construction and industrial maintenance. Cuts leather, rubber, rope, fiberglass, acetates and more.