The FAB Defense 7-Position QR Tactical Folding Grip mounts to picatinny rail. So if you have a picatinny rail adapter on the underside of your Beretta CX4 Storm it will work. But from what information I can find the Beretta CX4 Storm comes from the factory with no available picatinny rail to mount the FAB Defense 7-Position QR Tactical Folding Grip.