The Float Stone is a hold item in Generation V, given by a man inside Drayden's house in Opelucid City. It's a very light stone which halves the weight of the Pokémon holding it. This reduces the damage taken by weight-based attacks such as Grass Knot and Low Kick. It also lowers the amount of damage done if the holder uses Heavy Slam, and increases the damage done to the holder by it.