Defense

This is the overall rating of how well your settlers can defend against attacks. The cheapest way to establish a good defense by building guard towers and posts. These require Wood and Steel only but will need a settler to man the posts. One settler can man three guard towers for a total of 6 points defense. You can also build fully automated and independent auto-turrets that contribute 5 defense points. More powerful turrets require more Power and Science perks before you can build them.