EASY BLADE CHANGES: Twist knob opens knife while remaining hinged at the back for easy blade changes (Hinge-Loc is a Registered Trademark) DOUBLE INTERLOCKING FIXED: Double interlocking knife design holds blade securely and prevents slipping HEAVY DUTY CONSTRUCTION: All metal aluminum die-cast construction includes a heavy-duty utility blade and an internal magnet that accurately positions the blade VERSATILE: Cuts drywall, roofing materials, linoleum, carpet and vinyl COMPATABILITY: Fits . 025" thick IVY Classic blades 11172 and 11178, and other heavy-duty utility blades