There are 5 types of Security System.
- Universal (EMP Bombs and Mk II EMP Bombs). These defend against all Unit types during attacks on your Base.
- Light Infantry (Electric Fences and Mk II Electric Fences). These defend against Light Infantry Units during attacks on your Base.
- Mechanized Infantry (Trip Mines and Mk II Trip Mines). These defend against Mechanized Infantry Units during attacks on your Base.
- Armor (Spider Drones and Mk II Spider Drones). These defend against Armor Units during attacks on your Base.
- Combat Aviation (Aerial Drones and Mk II Aerial Drones). These defend against Combat Aviation Units during attacks on your Base.
In order to start hiring Mk II Security Systems, you need to research the Mk II Security Tech.
Security Systems will only defend against an attack that contains their respective Units. For example, if you hired Light Infantry Security Systems (Electric Fences), and an enemy attacked you with Mechanized Infantry Units, the Electric Fences will not take part in your Base defense.
Each Security System type has 3 main stats. These can be improved by researching the following Techs:
- Security System Power
- Security System Limit (the number of Systems you can hire at one time)
- Hiring Speed
You can hire both types of Security System Units in your base once you have unlocked Mk II Systems. For example, you can hire 40 Electric Fences at your Base, and then another 40 Mk II Electric Fences once you have unlocked both the maximum amount for both types and the Mk II System Tech.