Melee Weapon Mastery (3.5e Feat)
From D&D Wiki
Prerequisites: Weapon focus(chosen), weapon specialization(chosen), base attack bonus 8 or higher
Benefits: Choose one type of weapon you have focus and specialization in and gain one of the following;
Bludgeoning: If your attack was successful opponent makes DC=25 fortitude or he is stunned for 1d4 rounds
Slashing/Piercing: Your critical threat range is increased by 1(stacking with improved critical)
