Core Lock Services recommends the Lockwood 355 Deadlock for home security. When installed by a qualified locksmith this is one of the best locks available. This one was installed in Turramurra and keyed to the same key as the rest of the house. It can be locked internally, ensuring that if a criminal breaks the glass beside the lock, they cannot turn the inside handle and open the door. This complies with most insurance company's requirements for security.