Monk Weaponry (3.5e Feat)
From D&D Wiki
Monastic Weapon Training [Monk]
You may use additional weapons for the purposes for Flurry of Blows.
Prerequisite: Dex 13, Flurry of Blows class ability
Benefit: You may choose one martial or simple weapon. Treat that weapon as a Monk Weapon for the purpose of Flurry of Blows.
Normal: You may only use specific Monk Weapons for Flurry of Blows.
Special: You may take this feat multiple times. For each time it is taken, choose a different weapon.