Hardness
Each object has hardness—a number that represents how well it resists damage. Each time an object is damaged, its hardness is subtracted from the damage. Only damage in excess of its hardness is deducted from the object’s Hit Points. On average, a sturdy piece of equipment (such as a weapon or a suit of armor) has a hardness equal to 5 + 2 × its item level. Any other piece of equipment has a hardness equal to 5 + its item level.
Source
Core Rulebook pg. 409