Prime-Line U 11449 High Security Door Reinforcement Lock, Matte Black, 3 in. Screws | Resists 800 lbs Force

• Ideal Use: Adds secondary security to swing-in doors to help resist forced entry and unauthorized access
• Dimensions & Compatibility: Fits swing-in doors of virtually any thickness; some installations may require mortising for proper fit
• Materials & Components: Durable aluminum construction with matte black finish; includes reinforcement lock and 3 in. hardened mounting screws
• Key Features: Spring-loaded, tamper-resistant design helps resist forced entry, lock picking, and lock bumping when engaged
• Fit Guidance: Requires pre-drilled 1/8 in. pilot holes for installation; compatible MP114498 finger pull sold separately for easier operation

• Prepare Door and Mark Position — Ensure your door swings inward. Decide the lock's placement, typically higher on the door for child access restriction or near the existing lock for maximum reinforcement. Mark the screw hole positions accurately.
• Drill Pilot Holes — Using a 1/8-inch drill bit, carefully drill pilot holes at the marked positions on both the door and the door frame. This ensures the hardened screws can be driven in smoothly and securely.
• Mount the Lock — Align the reinforcement lock with the pilot holes on the door. Use the included three 3-inch hardened screws to attach the lock firmly to the door. Ensure it operates smoothly before fully tightening.
• Engage and Test — Test the lock by engaging its spring-loaded mechanism. Ensure it securely fastens into the strike plate on the frame. Verify that the door cannot be easily forced open from the outside when the lock is engaged.

Typical situations where Prime-Line U 11449 High Security Door Reinforcement Lock helps — illustrative scenarios, not customer reviews.