Quality: The door lock is high quality made of solid and reliable steel. This sturdy chain works as a chain lock for the front door with the added benefit of a door locking mechanism allowing the front door to be fully released from the outside with a key. SECURITY: prevents the door from opening far enough for entry, keeping the user safe, allowing them to answer their door without facilitating access to their home. This door chain lock also helps prevent young children from opening the door when installed out of their reach. Soft Action: This chain lock has smooth operation and will prevent the chain from snagging or sticking unnecessarily. Internal door locks don't have to be a burden that makes you dread having to pry open.They should just be an added door safety feature to keep you safe, just like this door limiter. UNIVERSAL: Door safety chains can be used on multiple materials. The interior door lock works on wood, composite, PVC and many other doors. The front door lock is protected by a polished brass coating to prevent wear. The XFORT door lock with key will work well on most surfaces. EASY INSTALLATION: No drilling or chiseling is required when purchasing a stainless steel chain Door chains come complete with all accessories and fixings needed for installation. This steel chain is surface mounted and comes complete with screws and 2 keys. No additional screws are needed