You can make an additional ranged attack.
Benefit: When making a full-attack action with a ranged weapon, you can fire one additional time this round at your highest bonus. All of your attack rolls take a –2 penalty when using Rapid Shot.
Pathfinder RPG Core Rulebook. Copyright 2009, Paizo Publishing, LLC; Author: Jason Bulmahn, based on material by Jonathan Tweet, Monte Cook, and Skip Williams.