Two Weapon Mastery

Source: Player's Handbook

You master fighting with two weapons at the same time, gaining the following benefits:

• You gain a +1 bonus to AC while you are wielding two melee weapons in each hand.

• If one of the two weapons that you are using is light then you can use a bonus action to attack with the second non-two-handed weapon.

• You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.