This is the Graham-Stetzer power line EM filter for dirty electricity (DE). 
This filter is a device that reduces the electrical noise present on the wiring of a home or building. This electrical disturbance is often also called dirty electricity, microsurge electrical pollution, electromagnetic interference (EMI), line noise, harmonic distortions etc. Dirty electricity is caused by modern non linear plug in devices, appliances, lights, switches and solar power. These all contribute to adding additional frequencies onto the wiring circuits which can also be measured within the electrical field. Each household adds to the DE, and this is passed onto neighbouring houses through the electric supply loop.
 
In our experience, 99% of homes have varying issues with dirty electricity.
 
Reducing DE will likely require between one to ten filters depending on your situation.
 
Frequency filtering range - 4kHz to 150kHz.
 
Please get in touch for more information about measuring your DE and about how to go about filtering.
 
Notes on the video
The video on this page shows the readings of a DE meter and the effects of the filter when activated. In this instance, not only do we have high levels of dirty electricity showing on the meter, but we also have the clear sound of AM radio. This is quite typical of many homes. The AM radio signal passes through as a ground wave past the home and jumps onto the electric circuits of the home. Some parts of this particular home had a quiet and noisy AM radio sound, the master bedroom just happened to have the clearest radio signal. As you can see, in this situation, one DE filter dropped out the noise down to low levels. 
 
Dirty electricity not only passes along the energised conductors we call electrical wiring, but it also exists in the air around the wires. Where the electric fields exist over our beds and seating which extends out 3 to 4 feet, so to does the dirty electricity. As shown here, very clear AM radio in the KHz range is also present on the circuits. This radio transmits 24/7 and so our night time slumber is infected with these high frequencies plus all the others, that affect us while we sleep.