Blades have a high-speed steel edge with titanium coating that keeps the blades cutting after others have quit. The patented bi-metal construction allows the blades to bend and flex without breaking. The 4 notch system allows the blade to extend further. Blades fit all standard utility knives and are great for cutting drywall, insulation, flooring, roofing, and more. No. 20350-GOLD5C: Type of blade: Utility - Titanium Edge, Pkg Qty: 5 No. 20351-GOLD50D: Type of blade: Utility - Titanium Edge, Pkg Qty: 50