That one is fine but why not get the DEI siren? It's better and probably cheaper. Louder isn't better. Louder is annoying. Louder is a ticket and possible impound for violating the noise ordinance.
If you install two sirens, use an inline fuse holder for each right where you branch the siren power wire into two. Use 7.5A fuses or lower. The reason for this is because scumbag thieves have a neat little trick where they cut your siren's wires and join them together. This shorts out the brain and will silence all sirens. If you have them fused, it will blow the fuse on the shorted siren and the other will be isolated allowing it to continue to blare.
