There are also differing part numbers (akin to finding out a top end MB will have the same guts BUT because it is in a top end car, the part number is different) that work. That top end siren price is commensurate with that top end car price as well (per-se). I was lucky enough to find the chirping replacement years ago, and wired it up in parallel to the OEM one. I suppose I should check again to see if both 'alarm' but one is hard enough on my ears. When I first installed the replacement and installed the original one in a different location, I SWEAR my hearing was damaged immensely. So, there are others that will work. I would snoop around a lot, find the least expensive 'newer' old one, and open it up first to see if replacing the batteries can give it a longer lease on life.