Loud, works with SmartThings with one tweak.

It works! It's really quite loud. It does require a very small screwdriver to attach the power leads, but it's pretty easy to set up. If you're using it with Smartthings, it will show up as a switch instead of a siren. If you log in to the Smartthings developer portal you can change it to a siren and then you can use it as such in the smart apps.

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