High quality material: solid stainless steel security lock, material: stainless steel, smooth surface, corrosion resistance, rust resistance, black electroplating coating, elegant, beautiful and gentleman. < p>Product size: 1.2mm thick super thick safety chain, door lock: 98×45mm (length×width), 210mm (length) welded steel chain, 100% durable. The thick widened chain that makes up this door lock is very strong. Security protection: The door chain lock can be opened from the inside, but cannot be opened from the outside , making you feel safer at home. You can also identify calls before the door is fully released. (Suitable for living room, apartment and hotel doors to give you extra security). Double Security: Added spring handle for security device, spring handle on door lock door must be lifted to open the lock. Therefore, the door lock can only be opened from the inside, not from the outside. The spring-loaded handle increases security and provides reliable anti-theft protection.