automatic door-locking system
Commonly refers to the system in apartment buildings where the entrance door locks automatically after entry or exit, often requiring a key or code to re-enter.
This apartment building has an automatic locking system, so it feels safe.
Because of the auto-lock system, you can't get in if you forget your key.
Variant with interpunct; less common in running text but seen in some contexts.
Loanword from English 'auto lock system'.