These feats are custom to Baldurs Gate: The Sword Coast Chronicles. They were implemented based on their Pencil and Paper incarnations and the work Obsidian had initially done to include them in NWN2.

Some homebrew modifications were made in order to translate them into the game environment. The Shield attack does not handle as on off-hand weapon for example although it does suffer a penalty that can be mitigated by the two weapon fighting feats. (e..a dual wielding)

It is also worth noting that if you have sneak attack dice, you will land sneak attacks after successfully shield slamming your opponent. The reason for this is that the daze causes the opponent to lose sight of you.

Shield Bash
Type of Feat: General
Prerequisites: None
Specifics: You can bash an opponent with a shield, using it as an off-hand weapon. Used this way, a shield is a martial bludgeoning weapon. For the purpose of penalties on attack rolls, treat a shield as a one-handed weapon. When you perform a shield bash, you may still apply the shield's shield bonus to your AC. Shield size impacts how hard it is to use as an off hand weapon as well as determining the amount of damage it does if it hits. Larger shields tend to be more difficult to bash with but do notably more damage. Shields can have critical hits when used as an off-hand weapon. A shield Bash counts as an extra attack and will happen the moment you switch it on and every six seconds afterwards while you are attacking.

The additional attack penalty while Shield Bashing mode is on is: 0 Light, 2 Heavy, 2 Tower. This excludes the default 'to hit' attack penalty for having a shield equipped, which adds another 2 in the case of the towershield. When uisng a towershield to bash the attacker incurs another momentary +2 during the Bash attack itself only. These penalties can be reduced or negated with the Two weapon (heavy & tower shields) and Improved Two Weapon Fighting feats (applicable to towershields only). The base damage for every shield type is d3 Light, d4 Heavy, d6 Tower plus the strength modifier of the bashing character including any and all buffs. If enabled modes such as power attack add extra damage at the appropriate penalty and a critical hit with the shield will double the total damage dealt. The shield cannot be made a Keen weapon by spell. Armor Class Enchantment bonuses on the shield do not affect the attack or damage rolls but it is possible to find shields that do above or below average damage. A shield bash executed during a charge counts as a free charge attack and gains all of the bonuses from Charging including a damage bonus from Powerful Charge and Greater Charge.
During the bash attack the Shield AC bonus is not deducted from the character's total armor class. (This is the Improved Shield Bash feat equivalent in PnP Terms) You gain an additional shield bash at BAB 11, and another one at BAB 21.
Use: Automatically if switched on

Weapon Focus [Shield Type]
Type of Feat: General
Prerequisites: None or able to use Tower Shields or previous Weapon Focus feat
Specifics: All shield types now have Weapon Focus, Greater Weapon Focus and Epic Weapon Focus feat variants. These increase your attack roll used when you attack using your shield.

Weapon Specialization [Shield Type]
Type of Feat: General
Prerequisites: None or able to use Tower Shields or previous Weapon Specialization feat
Specifics: All shield types now have Weapon Specialization, Greater Weapon Specialization and Epic Weapon Specialization feat variants. These increase your damage roll used when you attack and hit using your shield.

Shield [Type] Specialization [Shield Type]
Type of Feat: General
Prerequisites: None or able to use Tower Shields
Specifics: All shield types now have [Type] Specialization feat variants. These increase your AC for the given shield type by 1. This feat stacks with all other forms of shield AC.

Agile Shield Fighter
Type of Feat: General
Prerequisites: Shield Bash, Dex 13, One of the Shield Specialization feats
Specifics: When making a shield bash and armed strike attack as part of a full attack action, your attack penalty is reduced by 2.
Use: Automatatic

Shield Charge
Type of Feat: General
Prerequisites: Shield Bash, Base Attack Bonus + 3
Specifics: If you hit an opponent with your shield as part of a charge action, in addition to dealing damage normally, you will perform a trip check without provoking an attack of opportunity. If you lose, the defender does not get to try to trip you in return. Size increasing or diminishing effects can affect your trip. (The +4 size bonus from Powerful Charge applies as well as a +4 for Improved Knockdown)
Use: Automatically once a Shield ability such as Shield Bash or Shield Slam hits a target during a charge or Selected

Shield Slam
Type of Feat: General
Prerequisites: Shield Bash, Shield Charge, Base Attack Bonus + 6
Specifics: As a combat action or as a charge action, you may make an attack with your shield against an opponent. If you hit, you force the target damaged by this attack to make a Fortitude saving throw (DC 10 + 1/2 character level + Str modifier) in addition to dealing damage normally. A defender who fails this saving throw is dazed for 1 round (until just before your next action). Constructs, oozes, plants, undead, incorporeal creatures, and creatures immune to critical hits cannot be dazed. A Shield Slam can cost you one or several attacks in the time it takes to execute during your combat round. A Shield Slam inflicts damage like a Shield Bash even if the opponent saves, as long as the Slam has connected.
Use: Selected

When you daze an opponent with your slam he is thrown off-balance, essentialy being flatfooted. Such an opponent is susceptible to sneak attacks and cannot perform any actions. This includes not being able to drink potions. This is unlike the normal daze effect that spells for example use which seems to protect against sneak attacks and allows dazed creature to drink potions. Daze Immunity does not prevent the Shield Slam daze.

Feats curtesy of Rasael, testing by the Quality Control Team.