Strapped Shield (Ex)

At 3rd level, a thunderstriker takes no penalty on attack rolls when using a weapon in two hands while wearing a buckler.

This ability replaces armor training 1.

Hardbuckler (Ex)

At 7th level, a thunderstriker may make shield bash attacks with a buckler as if it were a light shield.

This ability replaces armor training 2.

Knockback Smash (Ex)

At 11th level, when a thunderstriker uses his buckler to attack, he gains a bonus equal to the enhancement bonus of the buckler on both attack and damage rolls.

This ability replaces armor training 3.

Hammer and Anvil (Ex)

At 13th level, a thunderstriker suffers only half the normal penalties for two-weapon fighting when using a buckler as his off-hand weapon.

This ability replaces weapon training 3.

Buckler Defense (Ex)

At 15th level, a thunderstriker retains partial use of his buckler even when using a weapon in both hands or in each hand (rather than losing his shield bonus until the beginning of his next turn). He gains a +1 shield bonus to AC and may apply the benefits of any feats he knows that require the use of a shield, but does not benefit from any magical properties his shield may possess.

This ability replaces armor training 4.

Balanced Bashing (Ex)

At 17th level, a thunderstriker no longer suffers two-weapon fighting penalties when using a buckler as his off-hand weapon.

This ability replaces weapon training 4.

Improved Buckler Defense (Ex)

At 19th level, a thunderstriker does not forfeit his shield bonus to AC from a buckler when fighting two-handed.

This ability replaces armor mastery.