Help Identifying Device

[coopns]

I think this is an old doorbell is it?
[img:right]https://drive.google.com/file/d/0B7Erx2QA6G6obzRsSVZsUVNVcEt0Y3JwNW5tWl9DSXNVTzNV/edit?usp=sharing[/img]

 

[AandPDan]

How big is it? It looks more like a thermostat housing if you ask me. That "hole" in the middle could be for a slot to adjust it.

Take some more pics.

 

[coopns]

Probably 6/8 inches. I always thought it was a door bell. It does have a 12 gauge wire hooked up. Just pulled it out of the wall more and it says "has spare bulb...detector". We don't have hard wired smoke/cm detectors though. All are on ceiling. I was thinking about taking cover off and putting a small plate cover back on and inserting back in wall. Bit rugged looking.

 

[OneEyeJack]

Take it apart.