Most security professionals agree that a single outer door lock will not provide adequate protection. For example, any tumbler-type lock with an opening for a key also provides an opening large enough for the lock to be picked. Thus, a combination of two different types of locks is recommended. Here are the most ordinary types of locks used in the home:

Spring Latch Locks: A popular and suitable lock that snaps closed whenever the beveled latch seats into a striker plate is the spring-latch lock. On the other hand, this lock can be easily forced by inserting through the door frame a thin blade or stiff plastic between the latch and the strike plate. Thus, a spring lock should always be augmented by a second lock of a different type.

Deadbolt Locks: The deadbolt lock features a solid, rectangular latch that forms a bolt between the door frame and the door itself. This lock is hard to force or jimmy and is a good choice as an auxiliary to any other key lock. 

Barrel-Type Bolt: A barrel-type bolt serves the same function as the deadbolt lock but is restricted to manual, internal operation merely. It may be used with an economical night-latch, and it is hard to force if it’s well made and installed appropriately.

Chain Locks: Used as an additional interior lock, the welded chain offers a precious security feature. It permits the user to open a door partially to exchange letters, messages, or small parcels with no completely unlocking the door. For proper mounting, the slide must be installed just above and slanting toward the chain.

Keep in mind, if you have taken possession of a new home or apartment, you should right away change the pin-tumbler locks on all exterior doors. A registered locksmith austin can typically alter the previous combination.