Monitors Flue Pipe Heat for Maximum Efficiency. Helps to Avoid Creosote Build-Up & Heat Loss. Easy to Install. Magnet and Sheet Metal Screw Included. Instructions for Use: Must be Installed on the Stove Pipe at a Distance of 18″ (45.7cm) Above the Stove. Magnet and/or Sheet Metal Screw Attaches to the Flue Pipe to Monitor Temperatures. A Durable and Highly Accurate Instrument to Aid in Monitoring Wood, Coal, Oil, Pellet and Gas Stove Flue Pipe Temperatures. This Instrument is for Singel Wall Stove Pipes Only. The Stove Pipe Thermometer Indicates the Most Efficient Temperature for your Stove. Too Hot and you are Losing Valuable Heat.Too Cold and you run a Risk of Creosote Building Up and Causing Blockages. Warnin The Thermometer Becomes Very Hot Whilst in Use. Always Wait Until your Stove has 100% Cooled Down Before Touching.