Armor protects the body at the cost of comfort and freedom of movement. Whether it is a simple a simple padding of leather to heavy plates of steel, armor is essential to the survival in the most dangerous of situations.
All armor has two values: the Absorption Value (AV) and the Offense Penalty (OP).
The AV is how much damage is subtracted from incoming damage per attacker per round. If your armor has an AV of 5, the first 5 damage you take from a given attacker each round is absorbed by the armor instead.
The OP is how much of your damage is reduced when attacking back - how restrictive the armor is, essentially. Your armor's OP is subtracted from the total damage you deal to each target each round.
Shields use the same AV and OP values, but those values only apply when you are actively choosing to Block. The shield's OP doesn't penalize you unless you also choose to Block in the same round (an additional action), and you don't gain any benefit from the shield's AV unlock you choose to Block.
Before spending money on armor, please remember that armor values of the same type don't stack - the highest one wins, ignoring all below it. Armor stacks with Shields and vice versa, but multiple armors don't stack, and neither do multiple shields.
Sample Armor and Shields
Below are some example armors and shields, but any AV from 1 to 10 can be made into an armor. The description is up to you, although Setting may have a say if it seems extreme (chainmail loincloths granting 10 AV, for instance).
Light Armor (Cloth, leather, bone)
Medium Armor (Studded leather, chain, breastplate)
Heavy Armor (Half plate, full plate)
Light Shield (Buckler, bracer)
Medium Shield (Round shield, Kite shield)
Heavy Shield (Tower shield)