All armor provides DR, and reduces damage from physical attacks. Some armor, like power armor, also protects against blast, fire, and other energy types. In addition to this DR, armor can also modify the wearer's Defense.
These rules are very similar to those presented in Unearthed Arcana for "Armor as Damage Reduction". We have simplified thing a bit (the Defense bonus depends only on armor type). Use the following table when converting from AC to Defense/DR:
| Armor Type | Defense | Damage Reduction |
|---|---|---|
| Light | 1 | AC -1 |
| Medium | 2 | AC -2 |
| Heavy | 3 | AC -3 |
The Defense bonus is applied if the wearer is proficient.
Example: A chain shirt normally provides a defense bonus of +4. Using these rules, it would give DR 3/-. A proficient wearer would get a defense bonus of +1.