A great product and an even greater value when compared to the more expensive FedSig SW300 unit. This comes with hardware (small 2 -piece plastic push rivets adn metal clips) to mount directly on top of a FedSig PA 150, 200, or 300 siren. Mine is on top of a 200 and looks great. Only complaint is that the instructions didn't say anything about this mounting option, I found this out by looking at the instructions for the FedSig SW300. Other than that, install was smooth, looks great. Thanks!!