[Premium Material] The door security chains lock is made of stainless steel, not easy to break, rust-proof and durable. Save more money for your life. [Make Your Home Safer] Lock-type design helps to identify a caller before the door is fully opened, with a spring anti-compression lock, the lock chain can only be opened indoors, avoiding forced entry, and improve your home security. [Widely Use]100% New Brand Front door chain with a lock is the perfect door locker for security and anti-theft of homes, schools, apartments, hotels, offices, restaurants, etc. [Easy To Install] Drill holes on the door frame according to the holes of the safety lock, then fix the chain lock with the included 4 screws. [Kindly Reminder] The product is suitable for all kinds of wooden doors, and can also be drilled on iron doors for use. It will cause damage to the wall and door, please purchase as needed.