Tower Shield Master

Your mastery of the use of towers shields expands your defensive capabilities. You gain the following benefits while you are wielding a tower shield:

• If you are the target of a ranged attack, you can use your reaction to receive three-quarters cover from your tower shield, increasing your AC for that attack roll by 5.
• If you aren't incapacitated, you can add your shield's AC bonus to any Dexterity saving throw you make against a spell or other harmful effect that targets only you.
• If you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you can use your reaction to take no damage if you succeed on the saving throw, interposing your shield between yourself and the source of the effect.