The door security chain latch is designed to identify a caller before the door is fully released and to prevent forced entry; When you purchase, please get the discount code on the product page to get a cheaper price. Allows the door to open to a gap of approximately 30-50mm, providing great security from the outside; The heavy-duty steel structure makes it incredibly robust against violent entry to maintain security; No drilling or chiseling required for installation. After installation, it cannot be unlocked from the outside. The security lock provides reliable protection for hotels, hotels, doors, storage rooms, windows, etc.