Armor is effectively protection, and a health boost.
Personal Armor: Edit
The Bulletproof Vest has 1000 HP, and gives no additional resistance.
The Armor Suit has much more health, and renders you invulnerable to small arms.
The Anti Explode Suit gives great resistance to explosives and immunity to Small Arms. It also gives more health.
Vehicle Armor: Edit
Vehicle Armor adds extra resistance to damage and more health.
Tanks: You have a choice of Extra Front Armor, which stacks with current front armor resistance, or Extra Side Armor, for better side protection.
ATV: Extra Health.