The center fire insulation straight blade (handle not included) quickly cuts through foam and fiber insulation products Such As blue or pink foam board insulation. Blade fits into standard utility knife handles and most reciprocating saws. The Non-serrated edge eliminates dust and debris – best tool available for cutting plasma rope. Crafted from high-quality tooling steel, these re-sharpenable carbon steel blades outlast most other blades. Note: We recommend purchasing the shortest blade that can cut all the way through your product to avoid wandering. The 4 inch blade is ideal for 3 inch thick foam board insulation, especially those with paper or foil backing. For other products See our 3 inch straight blade and 7 inch straight blade.