Twin Weapon Fighting Style

You fight with skill and grace using identical weapons. While wielding the same weapon type in both your main hand and your offhand and you are proficient with the weapon, you gain the following benefits:

• When you use the attack action on your turn, you can make one attack with your offhand weapon without using a bonus action. You may not use your bonus action to make an offhand weapon attack this turn. This attack otherwise follows the same rules as normal offhand attacks.
• If you hit the same opponent with your main weapon and your offhand weapon on your turn, it takes extra damage equal to your proficiency bonus.