I do not know a lot about this item I was only able to find a couple pictures of it. I know it's not complete because the original one I believe it had a dome on it. I picked this up at a sale several months back it's just been sitting on top of my to do pile it actually cleaned up really well.   As you can see in the pictures there is a crease towards the bottom it, straight across it measures 18×18 inches. I'm not sure if the thermometer itself is accurate or not so I'm gonna say it's not working.  If you have any questions feel free to ask and as usual thank you for looking