This is an adapter to allow the use of older Kidde Smoke Detector mounts for the new tiny ones. I don't know why Kidde changed the mount but the new one is not usable if changing a smoke detector which was mounted in a round electrical box. With this adapter, I was able to mount the new smoke detector in the electrical box with the old mounting plate. I'm adding this in case anyone else finds themselves in a similar situation. Hopefully Kidde will change the mounts back so that they can be mounted in the round electrical boxes.

I included the SketchUp files if anyone wishes to modify it.