Official Description
When thrown, the decoy grenade emulates the sound of the most powerful weapon you are carrying, creating the illusion of additional supporting forces.
Additional Information
The Decoy Grenade is a new grenade to the Counter-Strike series featured in Counter-Strike: Global Offensive. Very cheap and useful, the decoy is meant to confuse and misdirect. Sparingly used, decoys can be effective in confusing enemy players long enough to get them killed. Decoy's are very easy to pick out due to the repetitive nature of their weapon's fire sound effects, so don't expect a lot of use out of a decoy that has been active longer than a few seconds..