IRWIN Tools Blue Blade Bi-Metal Utility Blade, 20-Pack (2084200) These utility knife blades have a welded, bi-metal design for a sharp edge and flexible body Stays sharper than traditional utility blades A shatter-resistant design adds safety Fits IRWIN utility knife handles and most other utility knives Pack of 20 blades Pack of 20 bi-metal utility knife blades Spring steel body resists breakage High speed steel cutting edge resists dulling Bi-metal technology creates a superior blade