If the Pokémon holding this item creates a sandstorm with the moves Sandstorm or Max Rockfall, or the Abilities Sand Stream or Sand Spit, it lasts eight turns instead of five turns. (Prior to Generation VI, it has no effect on Sand Stream, which creates a sandstorm with indefinite length in those games.)
In the Generation VII games, if a sandstorm has its duration extended by the Smooth Rock, the turn counter on the user interface for these effects will indicate that it lasts for 8 turns for the player whose Pokémon used the move, while it will display that it lasts for 5 turns for their opponent. After 5 turns of sandstorm have passed, the user interface will display that it lasts for 8 turns for both players.
||A Pokémon hold item that extends the duration of the move Sandstorm used by the holder.
|A Pokémon held item that extends the duration of the move Sandstorm used by the holder.
|An item to be held by a Pokémon. It extends the duration of the move Sandstorm when used by the holder.
||An item to be held by a Pokémon. When the holder changes the weather to a sandstorm, the storm will persist for longer than usual.