[Quick Lock]There is a steel ball embedded in a movable handle, providing smooth operation. It is a kind of improved alternative to replace door chain locks. When you need to lock quickly the door guard in case of emergency, just move the swing bar to attach. [Durable and ]The door security is made of zinc alloy, which is not easily broken and structurally deformed. The surface is polished and brushed nickel, which allows it to be anti-rust. She will always look new and will never be damaged or discolored. [Child Protector]One of the important functions of this door chain restrictor is to protect children. Install the door guard high enough, where your children cannot reach, so that the children cannot open the front door and prevent strangers from breaking into the house. [Wide Application]The lock can open the door at a distance of 30-50mm approximately, which can see the outside with great security. Door restrictors allow you to identify visitors when it's not practical to have them to let in. You can also open the door slightly but lock it with a door security bar and ventilate the room. [Suitable for Multiple Occasions]The front door lock prevents forcible entry, such as bedroom door lock, window guard, front door chain lock, the patio door security lock, the door lock from hotel door, in storage rooms, veranda/patio and French doors etc. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-YJL official store