

A skill bonus however will not function unless the character has at least 1 point invested in the specified skill.

Class Mod skill bonuses do stack, even if a specific skill is maxxed (5/5), up to a total maximum of 11 ranks in any skill. They are class specific upgrades that provide benefits to the character (or the entire team) by offering a wide variety of bonuses such as amplifying a character's damage, healing, increasing character health or shield capacity, reducing reload times, increasing skill ranks, etc. Class Mods, or COMs (short for Class Optimization Modules), are influential items in Borderlands 2.
