From Compendium of Worldly Lore
Needs review
Source: Player's Handbook
Description: You can deflect incoming arrows, as well as crossbow bolts, spears, and other projectile or thrown weapons.
Prerequisites: DEX 13, Improved Unarmed Strike
Required for: Grappling Block, Infinite Deflection, Reflect Arrows, Snatch Arrows
You must have at least one hand free (holding nothing) to use this feat. Once per round when you would normally be hit with a ranged weapon, you may deflect it so that you take no damage from it. You must be aware of the attack and not flat-footed. Attempting to deflect a ranged weapon doesn't count as an action. Unusually massive ranged weapons, such as boulders hurled by giants, and ranged attacks generated by spell effects, such as Melf's acid arrow, can't be deflected.