Use to detect if your roof and gutter cable or pipe heating cable is operating. It works with all brands of pipe heating and roof and gutter cables. To use, simply plug the cable you want to monitor into the Current Sensing Device and observe the indicator light. When the light is on, the cable is working. It is also an ideal retrofit product for mobile home pipe heating cables as well as other electrical devices such as heat lamps, engine block heaters, soil warming cables and some space heaters. Model 18900 has a 10-foot cord, sensor with light on cord opposite of plug and a receptacle with a piggyback plug design. Should be used with GFCI protected outlet.