On my insert I can place it on top of the 5/16 steel top, which I believe is the best location. Anyway, I did the oven test and it came out 150F below what it should have read.. Okay, so I tapped and rapped the spring coil and tried again, and this time the test was bang on. Which means on the second test it was oven=400 and stove top =400.. This therm is a Imperial (kel kem) any one else use one of these? Not really a big deal, kinda got the handle on my new insert anyway,, just wondering if anyone else finds these cheapies kinda, well lets say not that realiable.