From AliensRL Wiki
Armors are the necessary protection between you and the many things trying to kill you. Only one armor may be equipped at a time, although they are by no means measured on a linear scale: some armors provide you with means other than simple protection, which you may find more suitable for a particular situation.
All armors have the following properties:
- Protection: this value is subtracted from all damage sources whenever the player is attacked.
- Note that all attacks, regardless of protection, cause at least one point of damage, unless specifically stated by the armor.
- Also note that protection also protects from the damage caused by radiation, but does not prevent the maximum HP degeneration that comes with it.
- Maximum Durability: this indicates the armor's total health. Durability loss is calculated as full (that is, unprotected) damage taken by an attack, divided by five, rounded down. Unless otherwise noted, durability drops by one on each attack (except radiation damage).
- Repair modifier: while an armor pack normally heals by a specific percentage, this value is multiplied by the repair rate to determine the total repair value to the armor.
- Bulk rating: this value affects how much knockback is dealt whenever an attack capable of knockback hits the player. This relates to the knockback modifier for aliens, but is otherwise directly related to damage.