You can wield two weapons or a double weapon without penalty.

Prerequisites: Dexterity 17, Dual Weapon Mastery I Feat, Dual Weapon Mastery II Feat, Base Attack Bonus +11

Effect: When you attack with two weapons, or with both ends of a double weapon as part of a Full Attack action, you take no penalty on your attack rolls. You only gain this benefit if you are wielding a weapon with which you are proficient.

Normal: If you use a Full Attack action to make more than one attack on your turn, you take a -10 penalty on all attack rolls for the round.

Additional Dual Weapon Mastery III Effects Edit

Reference Book: Star Wars Saga Edition Starships of the Galaxy

Vehicle Weapons cannot be used in one hand, so this Feat has no effect on them.