A Magnetic Stove Pipe Thermometer allows you to monitor the operating flue temperature of your stove. The thermometer should be installed on the face of the flue pipe no more than 6″ above the top of the stove. For added security, the wire (supplied) passes through the two holes in the front and secures to the pipe. This is a fail safe should the thermometer lose its magnetism over time. Not suitable for twin wall pipe.