The Combine lock is a door lock used in addition to a door handle that mechanically prevents the door from being opened unless it is disabled from a Combine Interface. They are used prolifically throughout City 17 and Combine bases to "gate" or restrict the player's (and non-Combines) access.
Combine locks are most commonly found in the residential apartments throughout City 17, to prevent unauthorized access and control areas that citizens (and the player) can access.
Combine personnel are able to unlock doors using a Combine Interface nearby, however, Alyx can use her EMP Tool to override Combine locks and gain access to restricted areas, as she does in Nova Prospekt.
In Half-Life 2: Episode One, the door locks demonstrate their ability to self-destruct: flashing red and emitting a beeping noise, then exploding, destroying the door they were attached to. This is often used by Overwatch Soldiers to forcefully enter buildings when they are aware hostiles are inside, surprising and disorienting them with a pack of soldiers quickly entering the room covered by the explosion's smoke.
List of appearances
- Half-Life 2 (First appearance)
- Half-Life 2: Deathmatch (Non-canonical appearance)
- Half-Life 2: Episode One
- Half-Life 2: Episode Two