Regular replacement of dirty air filters help reduce indoor pollution, allergens, and extends the life of your air system. With the Air Filter Alarm you'll never have to worry (or forget) about dirty air filters. This alarm will let you know when it is time to change the filter on your air conditioning or heating system by alerting you with a pleasant tone. Easily attaches to the air filter (on the blower side) with push-on pins.Clean Air The EPA has consistently ranked indoor air pollution among the top five environmental risks to public health. Failing to change your air filters on a regular basis can expose you to health risks. The Filtertone Air Filter Alarm reminds you to replace filters when needed by emitting a pleasant tone to alert you that it is time for a change. Eliminates Guesswork The Filtertone is easy to install - just attach it to you home air conditioner or heating furnace filter. As dirt builds up, it produces an increase in pressure which triggers the tone. You can enjoy the savings in utility bills that a clean, efficient system provides, and extend the life of heating and air conditioning units because they will no longer be straining to force air through clogged filters.