Product Description These IRWIN Bi-Metal Utility Knife Blades have a welded, bi-metal design for a sharp edge and flexible body and maintain sharpness up to 3 times longer than traditional carbon blades. A shatter-resistant design adds safety. Each utility blade fits most utility knife handles. Amazon.com The Irwin 2084200 Blue Blade Bi-Metal Utility Blade uses bi-metal technology to create a blade with superior performance and shatter-resistant ruggedness. The spring steel body has superior flexibility to resist breakage under stress, and the high speed steel cutting edge resists dulling. This pack includes 20 blades. From the Manufacturer The Irwin Blue Blade is a revolutionary, unbreakable utility blade. It's bi-metal technology sets new standards of performance, by providing an unbreakable blade that stays sharp three times longer than the next best utility blade. See more