Maybe I am being overly anal but when I follow the directions the probe seems too loose to me. I purchased a condar fluegard probe thermometer and drilled through both layers of the doublewall stovepipe with a 3/16" bit. Then enlarged the outer hole with a 1/4" drill bit. I slid the magnet onto the probe first and then the eyelet and put the probe into the stovepipe. I think the eyelet bottoms out on the inner layer of the double wall stovepipe, so I swapped the magnet and eyelet and it sits a lot better now. Photo 1 - instructions Photo 2 - condar fluegard thermometer Photo 3 - magnet and then eyelet slid onto probe Photo 4 - probe slid into stovepipe Photo 5 - swapped magnet and eyelet and then slid probe back into stovepipe.